This document provides an overview of density functional theory and methods for modeling strongly correlated materials. It discusses the limitations of standard DFT approaches like LDA for strongly correlated systems and introduces model Hamiltonians and correction methods like LDA+U, LDA+DMFT, self-interaction correction, and generalized transition state to better account for electron correlation effects. The document outlines the basic theory and approximations of DFT, including Kohn-Sham equations and the local density approximation, and discusses basis set approaches like plane waves, augmented plane waves, and pseudopotentials.
BoltzTraP is a software tool that uses linearized Boltzmann transport theory to calculate electronic transport properties from first-principles band structures. It can calculate properties like electrical conductivity, Seebeck coefficient, and electronic thermal conductivity. The document discusses applications of BoltzTraP to analyze transport properties of metals and thermoelectric materials. Key applications highlighted include analyzing anisotropy, resistivity temperature dependence, and optimizing the electronic structure of materials for high thermoelectric performance.
1. Hartree-Fock theory describes molecules using a linear combination of atomic orbitals to approximate molecular orbitals. It treats electrons as independent particles moving in the average field of other electrons.
2. The Hartree-Fock method involves iteratively solving the Fock equations until self-consistency is reached between the input and output orbitals. This approximates electron correlation by including an average electron-electron repulsion term.
3. The Hartree-Fock approach satisfies the Pauli exclusion principle through the use of Slater determinants, which are antisymmetric wavefunctions that go to zero when the spatial or spin coordinates of any two electrons are identical.
1. Hartree-Fock theory describes molecules using a linear combination of atomic orbitals to approximate molecular orbitals. It treats electrons as independent particles moving in the average field of other electrons.
2. The Hartree-Fock method involves iteratively solving the Fock equations until self-consistency is reached between the input and output orbitals. This approximates electron correlation by including an average electron-electron repulsion term.
3. The Hartree-Fock method satisfies the Pauli exclusion principle through the use of Slater determinants, which are antisymmetric wavefunctions that go to zero when the spatial or spin coordinates of any two electrons are identical.
The document discusses ab initio molecular dynamics simulation methods. It begins by introducing molecular dynamics and Monte Carlo simulations using empirical potentials. It then describes limitations of empirical potentials and the need for ab initio molecular dynamics which calculates the potential from quantum mechanics. The document outlines several ab initio molecular dynamics methods including Ehrenfest molecular dynamics, Born-Oppenheimer molecular dynamics, and Car-Parrinello molecular dynamics. It provides details on how these methods treat the quantum mechanical potential and classical nuclear motion.
This document provides an overview of density functional theory and methods for modeling strongly correlated materials. It discusses the limitations of standard DFT approaches like LDA for strongly correlated systems and introduces model Hamiltonians and correction methods like LDA+U, LDA+DMFT, self-interaction correction, and generalized transition state to better account for electron correlation effects. The document outlines the basic theory and approximations of DFT, including Kohn-Sham equations and the local density approximation, and discusses basis set approaches like plane waves, augmented plane waves, and pseudopotentials.
BoltzTraP is a software tool that uses linearized Boltzmann transport theory to calculate electronic transport properties from first-principles band structures. It can calculate properties like electrical conductivity, Seebeck coefficient, and electronic thermal conductivity. The document discusses applications of BoltzTraP to analyze transport properties of metals and thermoelectric materials. Key applications highlighted include analyzing anisotropy, resistivity temperature dependence, and optimizing the electronic structure of materials for high thermoelectric performance.
1. Hartree-Fock theory describes molecules using a linear combination of atomic orbitals to approximate molecular orbitals. It treats electrons as independent particles moving in the average field of other electrons.
2. The Hartree-Fock method involves iteratively solving the Fock equations until self-consistency is reached between the input and output orbitals. This approximates electron correlation by including an average electron-electron repulsion term.
3. The Hartree-Fock approach satisfies the Pauli exclusion principle through the use of Slater determinants, which are antisymmetric wavefunctions that go to zero when the spatial or spin coordinates of any two electrons are identical.
1. Hartree-Fock theory describes molecules using a linear combination of atomic orbitals to approximate molecular orbitals. It treats electrons as independent particles moving in the average field of other electrons.
2. The Hartree-Fock method involves iteratively solving the Fock equations until self-consistency is reached between the input and output orbitals. This approximates electron correlation by including an average electron-electron repulsion term.
3. The Hartree-Fock method satisfies the Pauli exclusion principle through the use of Slater determinants, which are antisymmetric wavefunctions that go to zero when the spatial or spin coordinates of any two electrons are identical.
The document discusses ab initio molecular dynamics simulation methods. It begins by introducing molecular dynamics and Monte Carlo simulations using empirical potentials. It then describes limitations of empirical potentials and the need for ab initio molecular dynamics which calculates the potential from quantum mechanics. The document outlines several ab initio molecular dynamics methods including Ehrenfest molecular dynamics, Born-Oppenheimer molecular dynamics, and Car-Parrinello molecular dynamics. It provides details on how these methods treat the quantum mechanical potential and classical nuclear motion.
This document discusses band theory and several models used to describe electron behavior in solids, including the free electron model, nearly free electron model, and tight binding model. It provides an overview of each model, including their assumptions and how they describe properties like electron energy and band gaps. The free electron model treats electrons as independent particles but fails to explain material properties. The nearly free electron model incorporates a periodic potential and allows electron wavefunctions and energy bands to be described. The tight binding model uses a superposition of atomic orbitals to approximate electron wavefunctions in solids where potential is strong.
This presentation is the introduction to Density Functional Theory, an essential computational approach used by Physicist and Quantum Chemist to study Solid State matter.
Quantum chemistry is the application of quantum mechanics to solve problems in chemistry. It has been widely used in different branches of chemistry including physical chemistry, organic chemistry, analytical chemistry, and inorganic chemistry. The time-independent Schrödinger equation is central to quantum chemistry and can be used to model chemical systems like the particle in a box, harmonic oscillator, and hydrogen atom. Molecular orbital theory is also important in quantum chemistry for describing chemical bonding in molecules.
Theoretical study of electronic properties of some aromatic ringsAlexander Decker
The document summarizes a theoretical study on the electronic properties of aromatic rings containing nitrogen atoms. Density functional theory was used to calculate properties of pyridine, pyrimidine, pyrazine and pyridazine, with nitrogen in different positions on a benzene ring. Key results showed adding nitrogen decreased energy gaps and improved electronic properties compared to benzene. Calculated properties included optimized structures, total energies, electronic states, energy gaps, ionization potentials, electron affinities, and vibration frequencies, with B3LYP/DFT showing good agreement with available experimental data.
Theoretical study of the effect of hydroxy subgroup on the electronic and spe...Alexander Decker
This document summarizes a theoretical study that used density functional theory calculations to investigate the effect of adding hydroxyl groups to the azulene molecule in different positions. The study found that adding hydroxyl groups (electron-withdrawing groups) decreases the energy gap of the molecules, making electrons easier to excite. It also decreases the ionization potential and increases the electron affinity, improving the electronic properties and making the molecules more soluble and conductive. Molecule 6, with hydroxyl groups in specific positions, was found to have the best properties for use as an n-type organic semiconductor. Vibrational frequency calculations showed good agreement with experimental data for the azulene molecule and identified characteristic vibrations induced by the addition of hydroxyl groups
Band structures plot the allowed electronic energy levels of crystalline materials. They reveal whether a material is metallic, semiconducting, or insulating, and provide other properties. Band structures are calculated in k-space, where k is a wave vector related to crystal orbital wavelengths. For a 1D chain of atoms, the energy depends quadratically on k. Higher dimensional crystals have more complex band structures due to interactions between orbitals in different directions. Calculating full band structures requires considering all orbitals within a material's Brillouin zone.
This document outlines topics related to semiconductor physics and optoelectronics physics, including:
1. Free electron theory of metals, Bloch's theorem, energy band diagrams, direct and indirect bandgaps, density of states, and the types of electronic materials including metals, semiconductors and insulators.
2. Lasers, which use stimulated emission of radiation to produce an intense, coherent beam of light. Key concepts covered include spontaneous emission, stimulated absorption, population inversion, and semiconductor lasers.
3. Photodetectors and noise sources, with reference made to the Fermi Golden Rule. The document provides an overview of key concepts that will be covered in more depth within these physics courses.
This document provides an overview of quantum phenomena and related concepts:
1) It explains key quantum concepts like electron energy levels, photon emission and absorption, the photoelectric effect, electron diffraction, radioactive decay, and how quantum theory differs from classical physics.
2) It discusses challenges in teaching quantum theory like its counterintuitive nature and need to link abstract ideas to observable phenomena.
3) It provides historical context on the development of quantum theory and unifications in physics, noting how quantum theory dissolved the classical distinction between particles and fields.
This document provides an overview of quantum phenomena and the key concepts of quantum theory. It summarizes that quantum theory differs from classical physics in profound ways, defying visualization and intuition. It describes discrete energy levels and photon absorption/emission leading to atomic line spectra. It also explains the photoelectric effect, matter waves of electrons, radioactive decay, and how quantum theory has unified our understanding of phenomena from the atomic to nuclear scale.
This document summarizes key concepts in condensed matter physics related to interacting electron systems.
It introduces the Hartree and Hartree-Fock approximations for modeling interacting electrons, which improve upon treating electrons independently but still do not fully capture electron correlation. The Hartree approximation models the average electrostatic potential felt by each electron from other electrons. Hartree-Fock further includes an "exchange" term to account for the Pauli exclusion principle.
It then discusses limitations of these approximations in capturing electron correlation, where the motion of each electron is correlated with all others due to both Coulomb repulsion and the Pauli principle. Capturing electron correlation is important for obtaining more accurate descriptions of materials' properties.
This document discusses atomic structure and periodicity. It begins by explaining electromagnetic radiation and its wave characteristics. It then discusses Planck's discovery that energy is quantized and Einstein's proposal that light can be viewed as particles called photons. Next, it explains the photoelectric effect and how it provided evidence that light behaves as particles. It discusses the Bohr model of the hydrogen atom and how it correctly predicted the atom's quantized energy levels but was fundamentally incorrect. Finally, it summarizes the development of the modern quantum mechanical model of the atom and periodic trends in atomic properties such as ionization energy and atomic radius.
Electron's gravitational and electrostatic force test.RitikBhardwaj56
This innovative ebook by John A. Macken delves deep into the fascinating world of electron interactions, shedding light on wave-based models and their impact on gravitational and electrostatic forces. Macken's theory 'Oscillating Spacetime: The Foundation of the Universe' revolutionizes our understanding of fundamental forces at the quantum level. From explaining key parameters without dimensions to comparing gravitational and electrostatic forces, this ebook offers a thorough exploration of wave-based models in electron interactions.
With a fresh perspective, this ebook is a key player in advancing physics education. It simplifies complex concepts through Macken's theory, providing valuable insights into fundamental forces for students and educators alike. The inclusion of natural units and dimensionless constants makes quantum mechanics more accessible, improving the learning process for students at every level. As a result, this ebook is an essential tool for classrooms, self-study, and research, contributing to the ongoing development of scientific knowledge in the field of physics.
STRUCTURE OF ATOM
Sub atomic Particles
Atomic Models
Atomic spectrum of hydrogen atom:
Photoelectric effect
Planck’s quantum theory
Heisenberg’s uncertainty principle
Quantum Numbers
Rules for filling of electrons in various orbitals
Density functional theory (DFT) is a computational quantum mechanics method used to investigate the electronic structure of many-body systems like molecules and solids. It functions by using functionals of the electron density rather than the many-body wavefunction. This makes calculations more efficient. DFT was developed based on the Hohenberg-Kohn theorems, which established that all ground state properties are uniquely determined by the electron density alone. This allowed modeling systems using functionals of the density rather than attempting to solve the complicated many-electron Schrodinger equation directly. DFT is now widely used in physics, chemistry, and materials science.
This document discusses electromagnetic radiation and atomic structure. It begins by explaining the wave characteristics of electromagnetic radiation like wavelength, frequency, and speed. It then discusses Planck's discovery that energy is quantized and Einstein's proposal that electromagnetic radiation consists of photons. The photoelectric effect is explained, providing evidence that light behaves as particles. The development of quantum mechanics and concepts like wave-particle duality, the Heisenberg uncertainty principle, and quantum numbers are summarized. The shapes and energies of atomic orbitals are described, along with how the periodic table developed based on patterns in elements' properties.
A dimensionless quantity described as a fundamental physical constant characterizing the coupling strength of the electromagnetic interaction. Introduced by Sommerfeld in 1916 to describe the spacing of splitting of spectral lines in multi-electron atoms, it is formed from four physical constants: electric charge, speed of light in vacuo, Planck's constant and electric permittivity of free space.
The inverse fine structure constant (=137.035999...) represents the spin precession whirl no. of the electron. The electron exhibits a slight precession due to an imbalance of electrostatic and magnetostatic energy levels. Electric charge is a result of this spin precession and represents a loop closure failure (torsion defect) similar to topological charge.
Rest mass results from quantum wave interference due to precession. Hence, electric charge, rest mass and the fine structure constant are interrelated and directly calculable.
1) The Born-Oppenheimer approximation separates the molecular Schrodinger equation into electronic and nuclear parts based on the large mass difference between electrons and nuclei.
2) It assumes that over short time periods, electrons adjust instantaneously to nuclear motions. This allows treating electronic motions separately for fixed nuclear positions.
3) Solving the electronic Schrodinger equation for different nuclear configurations provides the potential energy surface for nuclear vibrations and rotations.
This document discusses a computational study of MAX phases using density functional theory. MAX phases are a group of materials that exhibit both metallic and ceramic properties. The study uses the WIEN2k software to calculate the electronic structure and properties of MAX phases like Cr2AlC and Cr2GaC from their density of states and band structure plots. Manganese is incorporated into the structures at varying concentrations to study their magnetic properties.
The document presents an analytical approach to estimate the range of alpha particles emitted from radon gas. It discusses the stopping power and range of charged particles as they pass through matter. Equations from Bohr and Bethe are provided to calculate stopping power. The results of simulations using SRIM2013 software to calculate alpha particle range and detection probabilities in air are presented and compared to previous SRIM versions. Tables and figures show trends in stopping power and range as alpha energy increases.
This document discusses atomic physics concepts including:
1) The quantum model of the hydrogen atom and its wave functions with allowed values for quantum numbers n, l, and ml.
2) Wave functions for the hydrogen atom including the 1s ground state and 2s excited state.
3) Atomic spectra including visible light spectra and x-ray spectra with selection rules and characteristic and continuous parts of x-ray spectra.
4) Population inversion, stimulated emission, absorption and the essential conditions for laser including population inversion, metastable states, and reflecting mirrors.
This document discusses band theory and several models used to describe electron behavior in solids, including the free electron model, nearly free electron model, and tight binding model. It provides an overview of each model, including their assumptions and how they describe properties like electron energy and band gaps. The free electron model treats electrons as independent particles but fails to explain material properties. The nearly free electron model incorporates a periodic potential and allows electron wavefunctions and energy bands to be described. The tight binding model uses a superposition of atomic orbitals to approximate electron wavefunctions in solids where potential is strong.
This presentation is the introduction to Density Functional Theory, an essential computational approach used by Physicist and Quantum Chemist to study Solid State matter.
Quantum chemistry is the application of quantum mechanics to solve problems in chemistry. It has been widely used in different branches of chemistry including physical chemistry, organic chemistry, analytical chemistry, and inorganic chemistry. The time-independent Schrödinger equation is central to quantum chemistry and can be used to model chemical systems like the particle in a box, harmonic oscillator, and hydrogen atom. Molecular orbital theory is also important in quantum chemistry for describing chemical bonding in molecules.
Theoretical study of electronic properties of some aromatic ringsAlexander Decker
The document summarizes a theoretical study on the electronic properties of aromatic rings containing nitrogen atoms. Density functional theory was used to calculate properties of pyridine, pyrimidine, pyrazine and pyridazine, with nitrogen in different positions on a benzene ring. Key results showed adding nitrogen decreased energy gaps and improved electronic properties compared to benzene. Calculated properties included optimized structures, total energies, electronic states, energy gaps, ionization potentials, electron affinities, and vibration frequencies, with B3LYP/DFT showing good agreement with available experimental data.
Theoretical study of the effect of hydroxy subgroup on the electronic and spe...Alexander Decker
This document summarizes a theoretical study that used density functional theory calculations to investigate the effect of adding hydroxyl groups to the azulene molecule in different positions. The study found that adding hydroxyl groups (electron-withdrawing groups) decreases the energy gap of the molecules, making electrons easier to excite. It also decreases the ionization potential and increases the electron affinity, improving the electronic properties and making the molecules more soluble and conductive. Molecule 6, with hydroxyl groups in specific positions, was found to have the best properties for use as an n-type organic semiconductor. Vibrational frequency calculations showed good agreement with experimental data for the azulene molecule and identified characteristic vibrations induced by the addition of hydroxyl groups
Band structures plot the allowed electronic energy levels of crystalline materials. They reveal whether a material is metallic, semiconducting, or insulating, and provide other properties. Band structures are calculated in k-space, where k is a wave vector related to crystal orbital wavelengths. For a 1D chain of atoms, the energy depends quadratically on k. Higher dimensional crystals have more complex band structures due to interactions between orbitals in different directions. Calculating full band structures requires considering all orbitals within a material's Brillouin zone.
This document outlines topics related to semiconductor physics and optoelectronics physics, including:
1. Free electron theory of metals, Bloch's theorem, energy band diagrams, direct and indirect bandgaps, density of states, and the types of electronic materials including metals, semiconductors and insulators.
2. Lasers, which use stimulated emission of radiation to produce an intense, coherent beam of light. Key concepts covered include spontaneous emission, stimulated absorption, population inversion, and semiconductor lasers.
3. Photodetectors and noise sources, with reference made to the Fermi Golden Rule. The document provides an overview of key concepts that will be covered in more depth within these physics courses.
This document provides an overview of quantum phenomena and related concepts:
1) It explains key quantum concepts like electron energy levels, photon emission and absorption, the photoelectric effect, electron diffraction, radioactive decay, and how quantum theory differs from classical physics.
2) It discusses challenges in teaching quantum theory like its counterintuitive nature and need to link abstract ideas to observable phenomena.
3) It provides historical context on the development of quantum theory and unifications in physics, noting how quantum theory dissolved the classical distinction between particles and fields.
This document provides an overview of quantum phenomena and the key concepts of quantum theory. It summarizes that quantum theory differs from classical physics in profound ways, defying visualization and intuition. It describes discrete energy levels and photon absorption/emission leading to atomic line spectra. It also explains the photoelectric effect, matter waves of electrons, radioactive decay, and how quantum theory has unified our understanding of phenomena from the atomic to nuclear scale.
This document summarizes key concepts in condensed matter physics related to interacting electron systems.
It introduces the Hartree and Hartree-Fock approximations for modeling interacting electrons, which improve upon treating electrons independently but still do not fully capture electron correlation. The Hartree approximation models the average electrostatic potential felt by each electron from other electrons. Hartree-Fock further includes an "exchange" term to account for the Pauli exclusion principle.
It then discusses limitations of these approximations in capturing electron correlation, where the motion of each electron is correlated with all others due to both Coulomb repulsion and the Pauli principle. Capturing electron correlation is important for obtaining more accurate descriptions of materials' properties.
This document discusses atomic structure and periodicity. It begins by explaining electromagnetic radiation and its wave characteristics. It then discusses Planck's discovery that energy is quantized and Einstein's proposal that light can be viewed as particles called photons. Next, it explains the photoelectric effect and how it provided evidence that light behaves as particles. It discusses the Bohr model of the hydrogen atom and how it correctly predicted the atom's quantized energy levels but was fundamentally incorrect. Finally, it summarizes the development of the modern quantum mechanical model of the atom and periodic trends in atomic properties such as ionization energy and atomic radius.
Electron's gravitational and electrostatic force test.RitikBhardwaj56
This innovative ebook by John A. Macken delves deep into the fascinating world of electron interactions, shedding light on wave-based models and their impact on gravitational and electrostatic forces. Macken's theory 'Oscillating Spacetime: The Foundation of the Universe' revolutionizes our understanding of fundamental forces at the quantum level. From explaining key parameters without dimensions to comparing gravitational and electrostatic forces, this ebook offers a thorough exploration of wave-based models in electron interactions.
With a fresh perspective, this ebook is a key player in advancing physics education. It simplifies complex concepts through Macken's theory, providing valuable insights into fundamental forces for students and educators alike. The inclusion of natural units and dimensionless constants makes quantum mechanics more accessible, improving the learning process for students at every level. As a result, this ebook is an essential tool for classrooms, self-study, and research, contributing to the ongoing development of scientific knowledge in the field of physics.
STRUCTURE OF ATOM
Sub atomic Particles
Atomic Models
Atomic spectrum of hydrogen atom:
Photoelectric effect
Planck’s quantum theory
Heisenberg’s uncertainty principle
Quantum Numbers
Rules for filling of electrons in various orbitals
Density functional theory (DFT) is a computational quantum mechanics method used to investigate the electronic structure of many-body systems like molecules and solids. It functions by using functionals of the electron density rather than the many-body wavefunction. This makes calculations more efficient. DFT was developed based on the Hohenberg-Kohn theorems, which established that all ground state properties are uniquely determined by the electron density alone. This allowed modeling systems using functionals of the density rather than attempting to solve the complicated many-electron Schrodinger equation directly. DFT is now widely used in physics, chemistry, and materials science.
This document discusses electromagnetic radiation and atomic structure. It begins by explaining the wave characteristics of electromagnetic radiation like wavelength, frequency, and speed. It then discusses Planck's discovery that energy is quantized and Einstein's proposal that electromagnetic radiation consists of photons. The photoelectric effect is explained, providing evidence that light behaves as particles. The development of quantum mechanics and concepts like wave-particle duality, the Heisenberg uncertainty principle, and quantum numbers are summarized. The shapes and energies of atomic orbitals are described, along with how the periodic table developed based on patterns in elements' properties.
A dimensionless quantity described as a fundamental physical constant characterizing the coupling strength of the electromagnetic interaction. Introduced by Sommerfeld in 1916 to describe the spacing of splitting of spectral lines in multi-electron atoms, it is formed from four physical constants: electric charge, speed of light in vacuo, Planck's constant and electric permittivity of free space.
The inverse fine structure constant (=137.035999...) represents the spin precession whirl no. of the electron. The electron exhibits a slight precession due to an imbalance of electrostatic and magnetostatic energy levels. Electric charge is a result of this spin precession and represents a loop closure failure (torsion defect) similar to topological charge.
Rest mass results from quantum wave interference due to precession. Hence, electric charge, rest mass and the fine structure constant are interrelated and directly calculable.
1) The Born-Oppenheimer approximation separates the molecular Schrodinger equation into electronic and nuclear parts based on the large mass difference between electrons and nuclei.
2) It assumes that over short time periods, electrons adjust instantaneously to nuclear motions. This allows treating electronic motions separately for fixed nuclear positions.
3) Solving the electronic Schrodinger equation for different nuclear configurations provides the potential energy surface for nuclear vibrations and rotations.
This document discusses a computational study of MAX phases using density functional theory. MAX phases are a group of materials that exhibit both metallic and ceramic properties. The study uses the WIEN2k software to calculate the electronic structure and properties of MAX phases like Cr2AlC and Cr2GaC from their density of states and band structure plots. Manganese is incorporated into the structures at varying concentrations to study their magnetic properties.
The document presents an analytical approach to estimate the range of alpha particles emitted from radon gas. It discusses the stopping power and range of charged particles as they pass through matter. Equations from Bohr and Bethe are provided to calculate stopping power. The results of simulations using SRIM2013 software to calculate alpha particle range and detection probabilities in air are presented and compared to previous SRIM versions. Tables and figures show trends in stopping power and range as alpha energy increases.
This document discusses atomic physics concepts including:
1) The quantum model of the hydrogen atom and its wave functions with allowed values for quantum numbers n, l, and ml.
2) Wave functions for the hydrogen atom including the 1s ground state and 2s excited state.
3) Atomic spectra including visible light spectra and x-ray spectra with selection rules and characteristic and continuous parts of x-ray spectra.
4) Population inversion, stimulated emission, absorption and the essential conditions for laser including population inversion, metastable states, and reflecting mirrors.
Similar to MAR_Comprehensive exam on density functional theorypptx (20)
AI for Legal Research with applications, toolsmahaffeycheryld
AI applications in legal research include rapid document analysis, case law review, and statute interpretation. AI-powered tools can sift through vast legal databases to find relevant precedents and citations, enhancing research accuracy and speed. They assist in legal writing by drafting and proofreading documents. Predictive analytics help foresee case outcomes based on historical data, aiding in strategic decision-making. AI also automates routine tasks like contract review and due diligence, freeing up lawyers to focus on complex legal issues. These applications make legal research more efficient, cost-effective, and accessible.
DEEP LEARNING FOR SMART GRID INTRUSION DETECTION: A HYBRID CNN-LSTM-BASED MODELijaia
As digital technology becomes more deeply embedded in power systems, protecting the communication
networks of Smart Grids (SG) has emerged as a critical concern. Distributed Network Protocol 3 (DNP3)
represents a multi-tiered application layer protocol extensively utilized in Supervisory Control and Data
Acquisition (SCADA)-based smart grids to facilitate real-time data gathering and control functionalities.
Robust Intrusion Detection Systems (IDS) are necessary for early threat detection and mitigation because
of the interconnection of these networks, which makes them vulnerable to a variety of cyberattacks. To
solve this issue, this paper develops a hybrid Deep Learning (DL) model specifically designed for intrusion
detection in smart grids. The proposed approach is a combination of the Convolutional Neural Network
(CNN) and the Long-Short-Term Memory algorithms (LSTM). We employed a recent intrusion detection
dataset (DNP3), which focuses on unauthorized commands and Denial of Service (DoS) cyberattacks, to
train and test our model. The results of our experiments show that our CNN-LSTM method is much better
at finding smart grid intrusions than other deep learning algorithms used for classification. In addition,
our proposed approach improves accuracy, precision, recall, and F1 score, achieving a high detection
accuracy rate of 99.50%.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Null Bangalore | Pentesters Approach to AWS IAMDivyanshu
#Abstract:
- Learn more about the real-world methods for auditing AWS IAM (Identity and Access Management) as a pentester. So let us proceed with a brief discussion of IAM as well as some typical misconfigurations and their potential exploits in order to reinforce the understanding of IAM security best practices.
- Gain actionable insights into AWS IAM policies and roles, using hands on approach.
#Prerequisites:
- Basic understanding of AWS services and architecture
- Familiarity with cloud security concepts
- Experience using the AWS Management Console or AWS CLI.
- For hands on lab create account on [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
# Scenario Covered:
- Basics of IAM in AWS
- Implementing IAM Policies with Least Privilege to Manage S3 Bucket
- Objective: Create an S3 bucket with least privilege IAM policy and validate access.
- Steps:
- Create S3 bucket.
- Attach least privilege policy to IAM user.
- Validate access.
- Exploiting IAM PassRole Misconfiguration
-Allows a user to pass a specific IAM role to an AWS service (ec2), typically used for service access delegation. Then exploit PassRole Misconfiguration granting unauthorized access to sensitive resources.
- Objective: Demonstrate how a PassRole misconfiguration can grant unauthorized access.
- Steps:
- Allow user to pass IAM role to EC2.
- Exploit misconfiguration for unauthorized access.
- Access sensitive resources.
- Exploiting IAM AssumeRole Misconfiguration with Overly Permissive Role
- An overly permissive IAM role configuration can lead to privilege escalation by creating a role with administrative privileges and allow a user to assume this role.
- Objective: Show how overly permissive IAM roles can lead to privilege escalation.
- Steps:
- Create role with administrative privileges.
- Allow user to assume the role.
- Perform administrative actions.
- Differentiation between PassRole vs AssumeRole
Try at [killercoda.com](https://killercoda.com/cloudsecurity-scenario/)
Software Engineering and Project Management - Software Testing + Agile Method...Prakhyath Rai
Software Testing: A Strategic Approach to Software Testing, Strategic Issues, Test Strategies for Conventional Software, Test Strategies for Object -Oriented Software, Validation Testing, System Testing, The Art of Debugging.
Agile Methodology: Before Agile – Waterfall, Agile Development.
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Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
2. Exploration of direct band gap double
perovskites A2AgIrCl6 (A= Cs, Rb, K): a DFT
study
Md. Abu Rayhan
ID No: 20PPHY002P
Session: 2020-21
Department of Physics
Chittagong University of Engineering & Technology (CUET)
Chittagong-4349, Bangladesh
2
Supervisor
Prof. Dr. Md. Ashraf Ali
3. • Introduction
• Literature review
• Motivation
• Objectives
• Methodology
• Results and discussions
• Conclusions
Outlines
3
4. Introduction
• Perovskite materials: Crystalline compounds with unique structure (ABX3). High
potential for solar cells, LEDs, due to excellent properties. Example- CaTiO3
• Types- i) single perovskites, ii) double perovskites
Single Perovskite (ABX3)
• Oxide perovskite (ABO3)
• Halide perovskite (ABF3)
• Nitrides perovskite
(ABN3)
Double perovskite (A2BBʹX6)
• Oxide
• Halide
4
6. Literature review
Author Compounds Property Study Journal
E. Greul et al. Cs2AgBiBr6 Structural and optoelectronic J. Mater. Chem. A, vol. 5, p.
19972, 2017.
N. Guechi et al. Cs2AgBiX6 (X= Cl, Br) Elastic, optoelectronic and
thermoelectric
J. Electron. Mater., vol. 47,
pp. 1533–1545, 2018.
W. Shi et al. Cs2MBiCl6 (M= Ag, Cu,
Na, K, Rb, and Cs)
Structural and opto-electronic J. Chem. Phys., vol. 153, p.
141101, 2020.
M. Nabi et al. Cs2CuMCl6 (M= Sb, Bi) Structural stability, electronic, elastic,
thermoelectric and optical
Sci. Rep., vol. 11, p. 12945,
2021.
Shruthi Nair et
al.
Cs2TlBiI6 Structural, electronic and optical J. Phys.: Condensed Matter,
vol. 31, p. 445902, 2019
T. Saha et al Cs2AgAsCl6 structural, mechanical, electronic,
thermodynamic, phonon and optical
Phys. Chem. Chem. Phys.,
vol. 24, p. 26609, 2022.
T. Y. Tang et al. A2CuSbX6 (A= Cs, Rb,
K; X= Cl, Br, I)
Physical and optoelectronic Chemical Physics, vol. 570,
p. 111897, 2023.
M. Caid et al. Cs2CuIrF6 Structural stability and optoelectronic J. Molecular Modeling, vol.
29, p. 178, 2023.
6
7. Motivation
These Double perovskites compounds are (A2AgIrCl6 (A= Cs,
Rb, K) composed of abundant and non-toxic elements, making
them environmentally friendly along with the cost effective and
time efficient.
No theoretical or practical work has been done on these
substances in order to determine physical properties qualities via
DFT computation.
The comprehensive study of these double perovskites also
contributes to fundamental scientific understanding.
7
8. Objectives
To study the structural stability such as tolerance factor, octahedral factor, new
tolerance factor.
To check the thermo-dynamical stability such as formation energy, binding energy
and decomposition energy and dynamical stability of the compounds.
To study the mechanical stability and elastic behavior.
To find out the energy gap of band structure and electron density of states.
To find the optical properties of the compounds for using in solar cells.
To find the suitability for use in solar cells and/or thermoelectric devices
8
9. Why Density Functional Theory?
9
Computational Methodology
DFT (Density Functional Theory)
The calculation of physical and chemical properties of multi- particle
systems (atoms, molecules or solids) require the exact determination of
electronic structure and total energy of these systems.
Schrödinger equation successfully explains the electronic structure of
simple systems and numerically exact solutions are found for small no. of
atoms and molecules.
This n-electron problem was solved when Kohn and Sham in 1965
formulated a theory concerning 3-dimensional electron density and energy
functionals.
Electron density n(r) plays central role instead of wave function ψ(r).
The problem of many-interacting particles system in static potential is
reduced to non-interacting single particle system in an effective potential.
10. Many body problem:
For large interacting system, we first need to consider a many particle wave
function.
Many body Hamiltonian for electron and nucleus is of the form given below
Hѱ (r,R,t) =E ѱ (r,R,t)
Innocent look of wave equation
Hѱ
=
M
m
e
Hѱ
=
=
Ѱ
=
ѱ
=
ѱ 10
11. Since the total Hamiltonian for electron and nucleus is:
then the hamiltonian for the electronic part will be
Approximations for solving many body problem
The Born-Oppenheimer approximation
Hartree approximation
Hartree-Fock method
Hohenberge- Kohen
Kohn-Sham approach (Walter Kohn and Lu.J.Sham)
The nuclei are much heavier than electrons.
They move much more slowly and hence neglect the nuclear kinetic energy.
The wave function separated into electronic and nuclear part and determine
motion of electrons with nuclei held fixed.
Hѱ =
=
Hѱ
=
11
12. Hartree approximation: One electron model
Reduce the complexity of electron-electron interactions.
Electrons are independent and interacts with others in an averaged way.
For an n-electron system, each electron does not recognize other as single entities but
as a mean field.
Hence, n-electron system becomes a set of non-interacting one-electron system where
each electron moves in the average density of rest electrons.
Self-consistent field procedure to solve the wave equation:
Vext = electron and
nuclei interaction
potential
VH = Hartree potential
(e-e interaction)
( )
+VH +Vext Ѱ(r) = EѰ(r)
E = E1+E2+E3+…..+En
R-nuclear
r- electron
12
13. Hartree method produced crude estimation of energy due to two
oversimplifications:
Hartree method does not follow two basic principles of quantum
mechanics: the antisymmetry principle and Pauli’s exclusion principle.
Does not count the exchange and correlation energies coming from n-
electron nature.
The Hartree method, therefore, was soon refined into the Hartree-Fock method.
Hartree-Fock method
Based on the one-electron and mean-field approach by Hartree, V.A. Fock enhanced the
methods to higher perfection. Fock and J.C. Slater in 1930 generalized the Hartree's theory to
take into account the antisymmetry requirement.
In HF method, the n-electron wave function approximated as a linear
combination of non-interacting one-electron wave function in the form of
Slater determinant.
Slater determinant
13
14. VH = Vij Hartree or Coulomb interaction
energy of two electrons
Ex = Exchange energy comes from the
antisymmetric nature of wave function in
the Slater determinant.
Difficulties with Hartree-Fock Theory:
A new approach has been developed known as Density Functional Theory
(DFT).
In 1964 Hohenberg and Kohn showed that schrodinger equation (3N dimensional e.g. 10 electrons
require 30 dimensions) could be reformulated in terms of electron density n(r) with non-interacting n
separate 3-dimensional ones.
The main objective of DFT is to replace the many-particle electronic wavefunction with the
electron density as the basic quantity.
The electron density n(r), the central player in DFT decides everything in an n-electron quantum state
where there is no individual electron density but a 3-dimensional density of electrons.
The addition of all the electron densities over the whole space naturally return to the total number of
electrons in the system.
The knowledge of overlapping of atomic electron density, roughly generate the electron density of the
solids.
This theory gives approximate solutions to both Exchange and Correlation Energies.
Correlation energy and
Problem of dealing 3N dimensional .
)ѱ(r) = E ѱ(r)
E = Ekin+ EH +Eext + Ex
14
15. The Fundamental Pillars of DFT
First Hohenberg Kohn (HK) theorem: The ground-state energy is a unique functional
of the electron density n(r).
This theorem provides one to one mapping between ground state wave function and
ground state charge density.
The ground state charge density can uniquely describe all the ground state
properties of system.
The fundamental concept behind density functional theory is that charge density (3-
Dimensional) can correctly describe the ground state of N-particle instead of using a
wave function (3N-Dimensional).
Second Hohenberg Kohn (HK) theorem: The electron density that minimizes the
energy of the overall functional is the true electron density.
If the true functional form of energy in terms of density gets known, then one could
vary the electron density until the energy from the functional is minimized, giving us
required ground state density.
This is essentially a variational principle and is used in practice with approximate
forms of the functional.
The simplest possible choice of a functional can be a constant electron density all
over the space.
15
16. Kohn- Sham Approach (1965):
KS replace the interacting n-electron system with a system of one-electron (non-
interacting) system in effective potential having the same ground state.
since the kinetic energy; E= Ekin+ Eext+EH +Ex+ Ec
int
non
non int
Ekin = Ekin + Ekin
where
E = Ekin + Ekin + Eext + EH +Ex + Ec
int
non int
E = Ekin + Eext + EH +Exc = F [n(r)] + Eext
non
16
17. Hence final KH equation has the form:
DFT in Practice: Kohn-Sham Self Consistency loop
17
18. 1. Local density approximation (LDA)
Exchange-correlation approximation
Approximation used to find out exchange-
correlation function.
Exchange-correlation energy functional is
purely local.
Ignores corrections to the exchange-
correlation energy at a point r due to nearby
inhomogeneities in the electron density.
2. Generalized Gradient Approximation (GGA)
Depends on local density and its gradient.
GGA uses information about the local electron density and also the local gradient in the
electron density. Though GGA includes more physical information than LDA. It is not
necessary that it must be more accurate. There are large number of distinct GGA functionals
depending on the ways in which information from the gradient of the electron density can
be included in a GGA functional.
18
19. Results & Discussion
Structural parameter
Cubic structure
Space group (Fm-3m, 225)
Lattice parameter (a = b = c;
α = β = γ = 90⁰)
Cs/Rb/K (0.25, 0.25, 0.25),
Ag(0.5, 0.5, 0.5), Ir (0, 0, 0),
and Cl (0.25, 0, 0).
Four formula unit (2:1:1:6)
Fig.2: Unit cell of Cs2AgIrCl6
19
20. Structural entity & stability
Table1: lattice parameter
Compound Lattice
constant
Cs2AgIrCl6 10.19
Rb2AgIrCl6 10.09
K2AgIrBr6 10.03
• Tolerance factor
• Octahedral factor
• New Tolerance factor
• Formation energy
• Binding energy
• Decomposition energy
𝑡𝐺 =
𝑅𝐴+𝑅𝑋
√2(
𝑅𝐵′+𝑅𝐵′′
2
+𝑅𝑋)
[1] 𝜏 =
𝑅𝑋
𝑅𝐵
− 𝑛𝐴 𝑛𝐴 −
𝑅𝐴 𝑅𝐵
ln 𝑅𝐴 𝑅𝐵
[3]
µ =
𝑅𝐵′+𝑅𝐵′′
2𝑅𝑋
[1]
𝐸𝑓 =
𝐸𝐴2𝐴𝑔𝐼𝑟𝐶𝑙6−𝑛𝐴×
𝐸𝐴
𝑘
−𝑛𝐴𝑔×
𝐸𝐴𝑔
𝑙
− 𝑛𝐼𝑟×
𝐸𝐼𝑟
𝑚
− 𝑛𝐶𝑙×
𝐸𝐶𝑙
𝑝
𝑁
[2]
𝐸𝑏 = 𝐸𝐴2𝐴𝑔𝐼𝑟𝐶𝑙6
− 𝑛𝐴 × 𝜇𝐴 − 𝑛𝐴𝑔 × 𝜇𝐴𝑔 − 𝑛𝐼𝑟 × 𝜇𝐼𝑟 − 𝑛𝐶𝑙 × 𝜇𝐶𝑙 [2]
∆𝐻𝐷 = 2𝐸 𝐴𝐶𝑙 + 𝐸 𝐴𝑔𝐶𝑙 + 𝐸 𝐼𝑟𝐶𝑙3 − 𝐸 𝐴2𝐴𝑔𝐼𝑟𝐶𝑙6
1. Liu, XiangChun; Hong, Rongzi; Tian, Changsheng (24 April 2008). "Tolerance factor and the stability discussion of ABO3-type ilmenite". Journal of Materials
Science: Materials in Electronics. 20 (4): 323–327
2. X. Du, D. He, H. Mei, Y. Zhong, and N. Cheng, “Insights on electronic structures, elastic features and optical properties of mixed-valence double perovskites
Cs2Au2X6 (X= F, Cl, Br, I),” Phys. Lett. A, vol. 384, no. 8, p. 126169, 2020.
3. C.J. Bartel, C. Sutton, B.R. Goldsmith, R.H. Ouyang, C.B. Musgrave, L. M. Ghiringhelli, M. Scheffler, New tolerance factor to predict the stability of perovskite
oxides and halides, article eaav0693, Sci. Adv. 5 (2) (2019)
20
23. Mechanical stability
C11 > 0, C11 - C12 > 0; C11 + 2C12 > 0; C44 > 0 and C11 > B > C12 [4]
Table.3: elastic parameter
Parameters Cs2AgIrCl6 Rb2AgIrCl6 K2AgIrCl6
Born
stability
127.79 90.86 78.25
35.70 19.55 17.47
16.22 18.28 12.83
92.09 71.31 60.78
199.19 129.96 113.19
19.48 1.27 4.64
Bulk modulus, B (GPa) 66.39 43.32 37.73
Shear modulus, G (GPa) 25.02 23.97 18.27
Young modulus, Y (GPa) 66.69 60.70 47.19
0.33 0.27 0.29
Pugh’s ratio, B/G 2.65 1.81 2.06
0.35 0.51 0.42
4. M. Born, K. Huang, and M. Lax, “Dynamical theory of crystal lattices,” Am. J. Phys., vol. 23, no. 7, p. 474, 1955.
Y > B > G
0.26 < ductile
1.75 < ductile
23
24. Electronic properties
• Band structure
• DOS (TDOS and PDOS)
• Direct band gap nature
• Effective mass of electrons and holes
Table.4: Band gap values of compounds
Compounds Band
gap
(eV)
Functional Band gap
nature
Effective mass
of electron, 𝒎𝒆
∗
Effective mass
of hole, 𝒎𝒉
∗
Cs2AgIrCl6 0.34
1.43
GGA PBE
Tb-mBJ
Direct
Direct
0.13 me
0.19 me
1.10 me
1.43 me
Rb2AgIrCl6 0.36
1.50
GGA PBE
Tb-mBJ
Direct
Direct
0.13 me
0.18 me
1.10 me
1.70 me
K2AgIrCl6 0.38
1.55
GGA PBE
Tb-mBJ
Direct
Direct
0.13 me
0.18 me
1.64 me
1.14 me
24
25. Fig. 4: Energy band structure of
Cs2AgIrCl6, Rb2AgIrCl6, K2AgIrCl6 by
GGA and TB-mBJ method.
25
26. Fig 5: Total and partial DOS of
Cs2AgIrCl6, Rb2AgIrCl6,
K2AgIrCl6 by TB-mBJ method
26
27. Fig. 6 Charge density of A2AgIrCl6 (A = Cs, Rb, K) compounds
27
28. Optical properties
Fig.7: Real and imaginary part of dielectric constant, refractive index, extinction coefficient of
the studied compound
28
31. Fig. 9 Calculated thermoelectric properties including a) Electrical conductivity, b)
Electronic portion of thermal conductivity, c) Lattice thermal conductivity, d)
Seebeck coefficient, e) Power factor (PF), and f) Figure of merit (ZT) of
Cs2AgIrCl6 (red color), Rb2AgIrCl6 (blue color), and K2AgIrCl6 (green color)
double perovskite.
31
32. Table 5: The calculated values of electrical conductivity (σ), electronic
conductivity (Ke), Seebeck coefficient (S), power factor (PF), and figure of merit
(ZT) for A2AgIrCl6 (A=Cs, Rb, K) at room temperature.
Material property Cs2AgIrCl6 Rb2AgIrCl6 K2AgIrCl6
Transport
properties (300 K)
𝜎 × 105
Ω ∙ m 0.66 0.67 0.68
Ke (Wm-1K-1) 0.97 0.85 0.91
S (μV/K) 189.30 176.23 182.20
PF (×10-3 Wm-1K-2) 2.40 2.09 2.25
ZT 0.74 0.74 0.83
32
33. Conclusions:
• The suggested compounds exhibit stability in dynamic, thermodynamic, and
mechanical aspects.
• The compounds exhibit a characteristic of ductility.
• The A2AgIrCl6 possesses a direct band gap.
• The energy gap corresponds to the visible range of electromagnetic waves, making it
applicable for utilization in solar cells, renewable energy technology, and
photocatalytic applications.
• Effective mass of electrons are small compared to effective mass of holes indicating
higher carrier mobility.
• The high absorption coefficients of 105 order and other optical constant, making their
suitability for opto-electronic application.
• The low reflectivity values (less than 13%) also indicates their high absorption
ability.
• A2AgIrCl6 (A = Cs/Rb/K) are desirable choice for potential candidates for use in
thermoelectric devices.
33