describes the complete history, mechanisms, instrumentation(jablonski diagram), types, comparision and factors affecting, applications of fluorescence and phosphorescence and describes about quenching and stokes shift.
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describes the complete history, mechanisms, instrumentation(jablonski diagram), types, comparision and factors affecting, applications of fluorescence and phosphorescence and describes about quenching and stokes shift.
The all the content in this profile is completed by the teachers, students as well as other health care peoples.
thank you, all the respected peoples, for giving the information to complete this presentation.
this information is free to use by anyone.
Fluorescence spectroscopy becomes a widely used tool at the interface of biology, chemistry and physics, because of its precise sensitivity and recent technical advancements. The measurements can provide information on a wide range of molecular processes including the interactions of solvent molecules with fluorophores, rotational diffraction of biomolecules, distance between sites of biomolecules, conformational changes and binding interactions. These advances in fluorescence technology are decreasing the cost and complexity of previously complex processes. Fluorescence spectroscopy is a highly developed and non-invasive technique that enables the on-line measurements of substrate and product concentrations or the identification of characteristic process states.
Fluorescence , Phosphorescence and photoluminescencePreeti Choudhary
luminescence, fluorescence and example of fluorescence, phosphorescence , Jablonski diagram, Photoluminescence.
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Introduction,Instrumentation, Classification of electronic transitions, Substituent and solvent effects, Classification of electronic transitions
Substituent and solvent effects
Applications of UV Spectroscopy
UV spectral study of alkenes
UV spectral study of poylenes
UV spectral study of α, β-unsaturated carbonyl
UV spectral study of Aromatic compounds
Empirical rules for calculating λmax.
Applications of UV Spectroscopy, Empirical rules for calculating λmax.
IR SPECTROSCOPY, INTRODUCTION, PRINCIPLE, THEORY, FATE OF ABSORBED RADIATION, FERMI RESONANCE, FINGERPRINT REGION, VIBRATIONS, FACTORS AFFECTING ABSORPTION OF IR RADIATION, SAMPLING TECHNIQUES, APPLICATIONS OF IR SPECTROSCOPY.
Fluorescence spectroscopy becomes a widely used tool at the interface of biology, chemistry and physics, because of its precise sensitivity and recent technical advancements. The measurements can provide information on a wide range of molecular processes including the interactions of solvent molecules with fluorophores, rotational diffraction of biomolecules, distance between sites of biomolecules, conformational changes and binding interactions. These advances in fluorescence technology are decreasing the cost and complexity of previously complex processes. Fluorescence spectroscopy is a highly developed and non-invasive technique that enables the on-line measurements of substrate and product concentrations or the identification of characteristic process states.
Fluorescence , Phosphorescence and photoluminescencePreeti Choudhary
luminescence, fluorescence and example of fluorescence, phosphorescence , Jablonski diagram, Photoluminescence.
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https://twitter.com/preetic27018281
Please like, share, comment and follow.
stay connected
If any query then contact:
chaudharypreeti1997@gmail.com
Thanking-You
Preeti Choudhary
Introduction,Instrumentation, Classification of electronic transitions, Substituent and solvent effects, Classification of electronic transitions
Substituent and solvent effects
Applications of UV Spectroscopy
UV spectral study of alkenes
UV spectral study of poylenes
UV spectral study of α, β-unsaturated carbonyl
UV spectral study of Aromatic compounds
Empirical rules for calculating λmax.
Applications of UV Spectroscopy, Empirical rules for calculating λmax.
IR SPECTROSCOPY, INTRODUCTION, PRINCIPLE, THEORY, FATE OF ABSORBED RADIATION, FERMI RESONANCE, FINGERPRINT REGION, VIBRATIONS, FACTORS AFFECTING ABSORPTION OF IR RADIATION, SAMPLING TECHNIQUES, APPLICATIONS OF IR SPECTROSCOPY.
Spectrofluorimetry or fluorimetry (www.Redicals.com)Goa App
The term fluorescence comes from the mineral fluorspar (calcium fluoride) when Sir George G. Stokes observed in 1852 that fluorspar would give off visible light (fluoresce) when exposed to electromagnetic radiation in the ultraviolet wavelength.
Fluorimetry is a technique used in analytical chemistry and biochemistry to measure the concentration of a substance in a sample by analyzing the fluorescence it emits when exposed to specific wavelengths of light. This technique is based on the principle of fluorescence, which is the emission of light (or photons) by a molecule when it absorbs photons at a shorter wavelength.
Here's how fluorimetry works:
Excitation: A sample is exposed to a specific wavelength of light, known as the excitation wavelength, which is typically in the ultraviolet or visible range. This excitation light is absorbed by the molecules of interest in the sample, causing them to move to higher energy states.
Emission: After absorbing the excitation light, the molecules return to their ground state by releasing energy in the form of fluorescent light at longer wavelengths. The emitted light is typically at a longer wavelength than the excitation light, and it is specific to the particular molecule or compound being analyzed.
Detection: A detector, such as a photomultiplier tube or a photodiode, is used to measure the intensity of the emitted fluorescent light. The detector is sensitive to the specific wavelength of light emitted by the target molecules.
Data Analysis: The intensity of the emitted fluorescent light is correlated with the concentration of the substance in the sample. By comparing the intensity of the emitted light to a calibration curve or standard, the concentration of the substance can be determined.
Fluorimetry has various applications in chemistry and biology. It is commonly used for quantifying the concentration of fluorescent dyes, proteins, nucleic acids (e.g., DNA and RNA), and other biomolecules. It is also employed in environmental analysis, drug discovery, and medical diagnostics.
One of the advantages of fluorimetry is its high sensitivity, which allows for the detection of very low concentrations of analytes. Additionally, it offers high selectivity because the emitted fluorescence is specific to the target molecule.
Overall, fluorimetry is a valuable analytical tool that helps researchers and scientists measure and analyze a wide range of substances with high precision and sensitivity
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
Model Attribute Check Company Auto PropertyCeline George
In Odoo, the multi-company feature allows you to manage multiple companies within a single Odoo database instance. Each company can have its own configurations while still sharing common resources such as products, customers, and suppliers.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
The Indian economy is classified into different sectors to simplify the analysis and understanding of economic activities. For Class 10, it's essential to grasp the sectors of the Indian economy, understand their characteristics, and recognize their importance. This guide will provide detailed notes on the Sectors of the Indian Economy Class 10, using specific long-tail keywords to enhance comprehension.
For more information, visit-www.vavaclasses.com
Palestine last event orientationfvgnh .pptxRaedMohamed3
An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
How to Split Bills in the Odoo 17 POS ModuleCeline George
Bills have a main role in point of sale procedure. It will help to track sales, handling payments and giving receipts to customers. Bill splitting also has an important role in POS. For example, If some friends come together for dinner and if they want to divide the bill then it is possible by POS bill splitting. This slide will show how to split bills in odoo 17 POS.
How to Create Map Views in the Odoo 17 ERPCeline George
The map views are useful for providing a geographical representation of data. They allow users to visualize and analyze the data in a more intuitive manner.
The Roman Empire A Historical Colossus.pdfkaushalkr1407
The Roman Empire, a vast and enduring power, stands as one of history's most remarkable civilizations, leaving an indelible imprint on the world. It emerged from the Roman Republic, transitioning into an imperial powerhouse under the leadership of Augustus Caesar in 27 BCE. This transformation marked the beginning of an era defined by unprecedented territorial expansion, architectural marvels, and profound cultural influence.
The empire's roots lie in the city of Rome, founded, according to legend, by Romulus in 753 BCE. Over centuries, Rome evolved from a small settlement to a formidable republic, characterized by a complex political system with elected officials and checks on power. However, internal strife, class conflicts, and military ambitions paved the way for the end of the Republic. Julius Caesar’s dictatorship and subsequent assassination in 44 BCE created a power vacuum, leading to a civil war. Octavian, later Augustus, emerged victorious, heralding the Roman Empire’s birth.
Under Augustus, the empire experienced the Pax Romana, a 200-year period of relative peace and stability. Augustus reformed the military, established efficient administrative systems, and initiated grand construction projects. The empire's borders expanded, encompassing territories from Britain to Egypt and from Spain to the Euphrates. Roman legions, renowned for their discipline and engineering prowess, secured and maintained these vast territories, building roads, fortifications, and cities that facilitated control and integration.
The Roman Empire’s society was hierarchical, with a rigid class system. At the top were the patricians, wealthy elites who held significant political power. Below them were the plebeians, free citizens with limited political influence, and the vast numbers of slaves who formed the backbone of the economy. The family unit was central, governed by the paterfamilias, the male head who held absolute authority.
Culturally, the Romans were eclectic, absorbing and adapting elements from the civilizations they encountered, particularly the Greeks. Roman art, literature, and philosophy reflected this synthesis, creating a rich cultural tapestry. Latin, the Roman language, became the lingua franca of the Western world, influencing numerous modern languages.
Roman architecture and engineering achievements were monumental. They perfected the arch, vault, and dome, constructing enduring structures like the Colosseum, Pantheon, and aqueducts. These engineering marvels not only showcased Roman ingenuity but also served practical purposes, from public entertainment to water supply.
We all have good and bad thoughts from time to time and situation to situation. We are bombarded daily with spiraling thoughts(both negative and positive) creating all-consuming feel , making us difficult to manage with associated suffering. Good thoughts are like our Mob Signal (Positive thought) amidst noise(negative thought) in the atmosphere. Negative thoughts like noise outweigh positive thoughts. These thoughts often create unwanted confusion, trouble, stress and frustration in our mind as well as chaos in our physical world. Negative thoughts are also known as “distorted thinking”.
3. Prepared & Presented by:
Sidra Safdar Durrani
M.Sc. Final year
Presented to:
Ms. Dr. Abida Parveen
For the Course of:
Photochemistry &
Radiation Chemistry
4. 4
WHAT IS MOLECULAR LUMINESCENCE ?
Chemiluminescence
Phosphorescence
Molecular Fluorescence
excitation resulting from a
chemical reaction
excitation by
absorption of photons:
PHOTOLUMINESCENCE
BASIC PRINCIPLE:
1st: molecules are excited (outer shell electrons like in
absorbance phenomenon)
2nd: excited species give an emission spectrum that
provides information for quantitation and
qualification
Fluorescence is short-lived, with luminescence ceasing
almost immediately (<10-5 sec) ,while phosphorescence
features luminescence from 10-4 to several seconds.
6. 6
SINGLET AND TRIPLET STATES
excited
singlet state
Excited triplet state is of less
energy than excited singlet
state.
Singlet to triplet transitions are
far less probable than
singlet/singlet transitions.
excited
triplet state
ground state
PAULI EXCLUSION PRINCIPLE: ―no
two electrons in an atom can have
the same set of 4 quantum
numbers‖, in other words:
two electrons in the same orbital
must have opposite spins (we say:
they are "paired": no net magnetic
field = the molecule will be
"diamagnetic"), molecule with
unpaired electrons (e.g. triplet state)
possess magnetic moment, are
attracted by magnetic field, are
called "paramagnetic"
Physicochemical properties of
molecules in triplet state can differ
significantly from those of singlet
state molecules.
7. 7
E L E C T R ON IC A N D V IB R A T ION A L
LEVELS
S0:
ground state of a molecule at ambient temperature,
all of the molecules in a solution
S1 and S2:
excited singlet states
T1:
lowest energetic triplet state, usually of less energy
than lowest energetic excited singlet state S1. Same E
S1
Each of these states features various
vibrational levels – this permits energetic
T1
similarity (and even equivalence) of
different electronic spin states of a molecule.
Because Singlet / triplet transitions are less probable than singlet /
singlet transition (because spin conversion is necessary) ,
thus the average lifetime of an excited triplet state is 10-4 sec
and more, while excited singlet state lifetime is 10-8 to 10-5 s.
8. 8
ELECTRON TRANSITIONS
INTERSYSTEM CROSSING
S2
S1
High E, Short λ
Low E, Long λ
Energy
T1
S0
VIBRATIONAL
RELAXATION due to
collisions between the
molecules of the excited
species and those of the
solvent
vibrational
levels
λ1
absorption
λ2
λ3
INTERNAL CONVERSION
when 2 levels are sufficiently close
energetically.
(reversal of spin), common in
molecules containing heavy
atoms or when paramagnetic
species are present (O2 in
solution) fluorescence is
decreased.
FLUORESCENCE
always from lowest
vibrational level of an
excited electronic state
PHOSPHORESCENCE
Deactivation from an ‘triplet” electronic
state to the ground state producing a
photon
9. 9
VIBRATIONAL RELAXATION I
1st Observation :
Upon excitation different vibrational levels can be
achieved, in solution any excess vibrational energy is
lost as consequence of collisions between the
molecules of the excited species and solvent molecules
Result:
Energy transfer to solvent and minuscule warming,
lifetime of vibrational excited species: 10-12 sec and
less.
Consequence:
Fluorescence (and Phosphorescence) of an
analyte in solution always occurs due to
electron transition from a vibrational ground
state.
10. 10
VIBRATIONAL RELAXATION II
2 n d O b s e r v a t i o n :
Upon luminescence different vibrational levels can be
achieved, in solution any excess vibrational energy is
lost
as
consequence
of
collisions
between
the
molecules of the excited species and solvent molecules
Consequence I:
fluorescence (and
phosphorescence) of
an analyte do not give
sharp signals but
diffuse bands.
C o n s e q u e n c e I I : T h e
fluorescence spectrum of
an analyte often is more
or less similar to its
absorbance spectrum.
11. Fluorescence – ground state to singlet
state & back
Phosphorescence -ground state to triplet
state & back
Fluorescence
10-5 to 10-8 s
Phosphorescence
10-4 to 10 s
Example of
Phosphorescence
0 sec
1 sec
11
13. 13
PHOSPHORESCENCE
After intersystem crossing from singlet to triplet state,
deactivation can occur by internal or external conversion
or by phosphorescence.
Since triplet-to-singlet conversions are comparatively
improbable events, the average lifetime of an excited
triplet state is 10-4 to 10 sec and more. Thus, emission
from such transition may persist for some time after
irradiation has been discontinued.
The other deactivation
transitions compete strongly
with phosphorescence, so
this phenomenon is usually
observed at low
temperatures, in highly
viscous media or at
molecules being adsorbed on
surfaces.
T1
S0
14. 14
THE SHAPE OF LUMINESCENCE SPECTRA
1. Phosphorescence and Fluorescence (emission)
Spectrum both come at longer wavelengths compared
to absorbance spectrum of the same molecule (Stokes
shift).
2. Phosphorescence
comes at lower energy =
at longer wavelengths than
fluorescence from the
same molecule.
3. Fluorescence (emission) Spectrum of a molecule is
more or less similar to its absorbance spectrum.
15. 15
How does glow-in-the-dark stuff work?
You see glow-in-the-dark stuff in all kinds of
places, but it is most common in toys like a
glow-in-the-dark yo-yo, a glow-in-the-dark
ball, a glow-in-the-dark mobile. If you have
ever seen any of these products, you know
that they all have to be "charged". You hold
them up to a light, and then take them to a
dark place. In the dark they will glow for 10
minutes. Some of the newer glow-in-the-dark
Light stick activation
stuff will glow for several hours.
occurs by simply cracking a
A color TV screen actually contains
light stick and allowing the
thousands of tiny phosphor picture
chemicals to mix.
elements that emit three different colors
(red, green and blue). In the case of a
fluorescent light, there is normally a
mixture of phosphors that together
create light that looks white to us.
16. 16
Each of PTI's diverse and versatile fluorometer systems is
designed with particular user needs in mind. The Quanta
Master™ 30 is a bench-top fluorometer that utilizes a pulsed
excitation source. The Quanta Master™ 30 is the most
sensitive fluorescence system using a pulsed light source
however if you ONLY require intensity based measurements
PTI'sQuantaMaster™ 40 is recommended.
17. INSTRUMENTATION
BASIC DESIGN
• components similar to UV/Vis
• spectrofluorometers: observe
• both excitation & emission
spectra.
Extra features for
phosphorescence
• sample cell in cooled Dewar
flask with liquid nitrogen
• delay between excitation and
emission
18. 18
LIGHT SOURCES OF FLUOROMETERS
IN SPECTROFLUORIMETER :
CONTINUOUS RADIATION REQUIRED
i) 75- to 450W high pressure xenon arc lamp,
emitting 300 to 1300 nm
large power supply needed (5 to 20 A at 15
to 30 V)
ii) tunable dye LASERs – comparatively expensive;
advantages: suitable for small samples ( L or
less), if highly monochromatic excitation is
required, or for remote sensing
19. 19
OTHER PARTS OF FLUOROMETERS
EXCITATION AND EMISSION
MONOCHROMATOR:
interference and absorption filters for filter
fluorometers
grating monochromators for
spectrofluorimeter
SAMPLE CELL:
cylindrical and rectangular cells of glass or quartz
any fingerprints are even more disturbing than
in absorbance spectroscopy
20. 20
OTHER PARTS OF FLUOROMETERS
DETECTOR:
the most common transducers are photomultiplier tubes
(PMT) run in photon counting mode
the final detector output (fluorescence signal) is the ratio
(division!) between the sample beam’s PMT signal intensity
and the reference beam’s PMT signal
photon counting mode (applied
for low intensity radiation):
analog signal is converted to a train
of digital pulses radiant power is
proportional to the number of pulses
per unit time.
21. 21
APPLICATIONS
TELEVISION TUBES ALSO USE PHOSPHORESCENCE. The tube
itself is coated with phosphor, and a narrow beam of electrons causes
excitation in a small portion of the phosphor. The phosphor then emits
red, green, or blue light—the primary colors of light—and continues to
do so even after the electron beam has moved on to another region of
phosphor on the tube. As it scans across the tube, the electron beam
is turned rapidly on and off, creating an image made up of thousands
of glowing, colored dots.
Cutaway rendering of a color CRT:
1. Three Electron guns (for red,
green, and blue phosphor dots)
2. Electron beams
3. Focusing coils
4. Deflection coils
5. Anode connection
6. Mask for separating beams for
red, green, and blue part of
displayed image
7. Phosphor layer with red, green,
and blue zones
8. Close-up of the phosphor-coated
inner side of the screen
22. 22
APPLICATIONS
PHOSPHORESCENT PIGMENTS
Our Phosphorescent pigments are a new type of long persistence
phosphorescent pigment of alkaline earth aluminate activated by rare
earth ions. The new type of pigment is used for many very different
technical and artistic purposes due to its characteristics. It can be used
in manufacturing paint; ink; plastic; rubber and films etc. It is
completely safe for the application in consumer products such as
clothing; shoes; caps; toys; stationery goods; watch; switch;
novelties; fishing tools and sporting goods. It has good effects in the
fields of building; decoration; traffic vehicle; military installations; fire
emergency system. It is especially suitable for the production of long
afterglow safety products such as warning; mandatory and escaperoute signs.