SlideShare a Scribd company logo
1 of 41
INFRARED SPECTROSCOPY
THEORY
PRESENTED BY: ANUPAMA RAMACHANDRAN
1st Year M Pharm Pharmacology
1
CONTENTS
• INTRODUCTION
• IR SPECTROSCOPY
• PRINCIPLE
• MOLECULAR VIBRATIONS
• COUPLED INTERACTIONS
• DEGREE OF FREEDOM
• SUMMARY
• REFERENCE
2
INTRODUCTION
• Spectroscopy is the measurement and interpretation of EMR absorbed or emitted
when the molecules or atoms or ions of a sample moves from one energy state to
another energy state.
• Spectroscopy is an instrumentally aided study of the interactions between matter
(sample being analyzed) and energy (any portion of the electromagnetic
spectrum)
3
SPECTROSCOPY
ABSORPTION SPECTROSCOPY EMISSION SPECTROSCOPY
*UV SPECTROSCOPY * FLUORIMETRY
*IR SPECTROSCOPY * FLAME PHOTOMETRY
*NMR SPECTROSCOPY
4
IR SPECTROSCOPY
• Energy of molecule = Electronic energy+ Vibrational energy + Rotational
energy
• IR spectroscopy is concerned with the study of absorption of infrared
radiation, which causes vibrational transition in the molecule. Hence, IR
spectroscopy also known as Vibrational spectroscopy.
• IR spectra mainly used in structure elucidation to determine the functional
groups.
5
6
IR REGION: 0.8 µm (800nm) to 1000 µm (1mm)
subdivided into
1.Near IR: 0.8-2 µm
2.Middle IR: 2-15 µm
3.Far IR: 15-1000 µm
Most of the analytical applications are confined to the middle IR region
because absorption of organic molecules are high in this region.
7
• GROUP FREQUENCY REGION:( 4000 to 1500 cm-1)
Contain relatively few peaks.
Associated with stretching vibrations.
Almost all the stretching vibrations are above 1450 cm-1.
IR stretching frequencies
8
FINGER PRINT REGION: (1500 – 400 cm-1 )
• Usually consist of bending vibrations within the molecule.
• pattern of peaks are more complicated & is much difficult pickout
individual bonds in this region
• Each compound produce its own unique pattern of peaks like a finger
print in this region .
9
• In pharmaceutical analysis, infrared radiation (mid IR) of wavelength
25µ to 2.5µ or wave numbers from 400cm-1 to 4000 cm-1.
• we use wave no. instead of wave length for mentioning characteristic
peak ,because wave numbers are larger values & easy to handle than
wave lengths.
• Wave no: no. of waves present per cm
•
1
𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡ℎ 𝑖𝑛 𝜇
× 104
= wave no. per cm
10
• Molecules are made up of atoms linked by chemical bonds. The
movement of atoms and the chemical bonds is like spring and balls
(vibration).
• This characteristic vibration are called Natural frequency of vibration.
PRINCIPLE OF IR SPECTROSCOPY
11
• When energy in the form of infrared radiation is applied ,then it
causes vibration between the atoms of the molecules and when,
Applied infrared frequency = Natural frequency of vibration
Then, Absorption of IR radiation takes place and a peak is observed.
Different functional groups absorb characteristic frequencies
of IR radiation. Hence gives the characteristic peak value. Therefore, IR
spectrum of a chemical substance is a finger print of a molecule for its
identification.
12
CRITERIA FOR A COMPOUND TO ABSORB IR
RADIATION
• 1. Correct wavelength of radiation
• 2. Change in dipole moment
1. Correct wavelength of radiation:
A molecule to absorb IR radiation, the natural frequency of vibrations
of some part of a molecule is the same as the frequency of incident
radiation.
13
2. Change in dipole moment
• A molecule can only absorb IR radiation when its absorption cause a
change in its electric dipole
• A molecule is said to have an electric dipole when there is a slight
positive and a slight negative charge on its component of atoms.
14
MOLECULAR VIBRATIONS
• Any change in shape of the
molecule.
2 types,
1) fundamental vibrations
2) non fundamental vibrations
15
FUNDAMENTAL VIBRATIONS
There are 2 types of vibrations:
1.Stretching vibrations
2.Bending vibrations
16
1.STRETCHING VIBRATIONS:
 Vibration or oscillation along the line of bond
Change in bond length
 Occurs at higher energy: 4000-1250 cm-1
2 types:
a)Symmetrical stretching
b)Asymmetrical stretching
17
a) Symmetrical stretching:
• 2 bonds increase or decrease in length simultaneously.
18
Symmetrical stretching
19
b) Asymmetrical stretching:
• in this, one bond length is increased and other is decreased
20
Asymmetrical stretching
21
2. BENDING VIBRATIONS
 Vibration or oscillation not along the line of bond
 These are also called as deformations
 In this, bond angle is altered
 Occurs at low energy: 1400-666 cm-1
 2 types:
a) In plane bending: scissoring, rocking
b) Out plane bending: wagging, twisting
22
a) In plane bending
i. Scissoring:
• This is an in plane bending
• 2 atoms approach each other
• Bond angles are decreased
23
Scissoring
24
ii. Rocking:
• Movement of atoms take place in the same direction.
25
Rocking
26
b) Out plane bending
i. Wagging:
• 2 atoms move to one side of the plane.
• They move up and down the plane.
27
Wagging
28
ii. Twisting:
• One atom moves above the plane and another atom moves below
the plane.
29
Twisting
30
COUPLED INTERACTIONS
• Interactions between vibrations can occur (Coupling) if the vibrating
bonds are joined to a single, central atom.
• This is because there is mechanical coupling interaction between the
oscillators.
Example: C=O (both symmetric and asymmetric stretching vibrations)
31
REQUIREMENTS FOR COUPLING
• The vibrations must be of the same symmetry species if interaction is
to occur.
• Strong coupling of stretching vibrations occurs when there is a
common atom between the two vibrating bonds.
• Coupling of bending vibrations occur when there is a common bond
between vibrating groups.
32
• Coupling is greatest when the coupled groups have approximately
equal energies.
• Coupling between a stretching vibration and a bending vibration
occurs if the stretching bond is one side of an angle varied by
bending vibration.
• No coupling is seen between groups separated by two or more bonds
33
34
FACTORS AFFECTING FREQUENCY OF IR
ABSORPTION
• Relative mass of the atom.
• Force constant of the bonds.
• Geometry of the atom.
35
DEGREE OF FREEDOM
• Fundamental vibration of molecule depend on degree of freedom.
• Each atom has 3 degree of freedom depend on x, y, z.
• For a molecule containing n no. of atoms has 3n degree of freedom.
• For non – linear molecule, 3 degree of freedom represent rotational &
transational motion.
• For non-linear, ( 3n -6) degree of freedom represent fudamental vibrations.
• For linear (3n-5) degree of freedom represent fundamental vibrations.
• All vibrational changes don’t appear as band.
• Only those vibrational changes that result in change in dipole moment
appear as band.
36
TYPICAL INFRARED SPECTRUM
37
38
SUMMARY
• Absorption spectroscopy.
• Vibrational transitions.
• Applied infrared frequency = Natural frequency of vibration.
• Structure elucidation to determine functional groups.
39
REFERENCES
1. Spectrometric identification of organic compounds, sixth edition,
Robert M. Silverstein & Francis X. Webster. Page no: 71 – 76
2. Principles of instrumental analysis, 6th edition, Douglas A. Skoog , E
James Holler, Stanley R Crouch . Page no: 430 – 455
3. Introduction to spectroscopy, Donald L Pavia, Gary M. Lampman,
James R. Vyvyan. Page no: 15 - 31
40
Thank you…
41

More Related Content

What's hot

Dispersive ir spectrophotometer
Dispersive ir spectrophotometerDispersive ir spectrophotometer
Dispersive ir spectrophotometerHimaniPeshavaria
 
UV-Visible Spectroscopy
UV-Visible SpectroscopyUV-Visible Spectroscopy
UV-Visible SpectroscopySudha Reddy
 
Infrared spectroscopy
Infrared spectroscopyInfrared spectroscopy
Infrared spectroscopyAsma Ashraf
 
Infrared spectroscopy(IR) & FTIR (Analytical Technique)
Infrared spectroscopy(IR) & FTIR (Analytical Technique)Infrared spectroscopy(IR) & FTIR (Analytical Technique)
Infrared spectroscopy(IR) & FTIR (Analytical Technique)VK VIKRAM VARMA
 
Nmr instrumentation Naveen Balaji
Nmr instrumentation Naveen BalajiNmr instrumentation Naveen Balaji
Nmr instrumentation Naveen BalajiNaveen Balaji
 
UV-VISIBLE SPECTROSCOPY
UV-VISIBLE SPECTROSCOPYUV-VISIBLE SPECTROSCOPY
UV-VISIBLE SPECTROSCOPYBinuja S.S
 
FTIR(Fourier transform infrared) spectroscopy
 FTIR(Fourier transform infrared) spectroscopy  FTIR(Fourier transform infrared) spectroscopy
FTIR(Fourier transform infrared) spectroscopy Preeti Choudhary
 
Infrared spectroscopy
Infrared spectroscopyInfrared spectroscopy
Infrared spectroscopyZainab&Sons
 
Relaxation in NMR
Relaxation in NMR Relaxation in NMR
Relaxation in NMR RM42
 
IR interpretation and sample handling
 IR interpretation and sample handling  IR interpretation and sample handling
IR interpretation and sample handling Afzaye Rasul
 
Interpretation of IR spectra
Interpretation of IR spectraInterpretation of IR spectra
Interpretation of IR spectrakeerthi Rangana
 
Infrared spectroscopy
Infrared spectroscopy Infrared spectroscopy
Infrared spectroscopy PV. Viji
 
Instrumentation of uv spectroscopy
Instrumentation of uv spectroscopyInstrumentation of uv spectroscopy
Instrumentation of uv spectroscopyArabinda Changmai
 
Nmr spectroscopy
Nmr spectroscopyNmr spectroscopy
Nmr spectroscopyAsma Ashraf
 

What's hot (20)

Dispersive ir spectrophotometer
Dispersive ir spectrophotometerDispersive ir spectrophotometer
Dispersive ir spectrophotometer
 
UV-Visible Spectroscopy
UV-Visible SpectroscopyUV-Visible Spectroscopy
UV-Visible Spectroscopy
 
Infrared spectroscopy
Infrared spectroscopyInfrared spectroscopy
Infrared spectroscopy
 
Nmr spectroscopy
Nmr spectroscopyNmr spectroscopy
Nmr spectroscopy
 
Infrared spectroscopy(IR) & FTIR (Analytical Technique)
Infrared spectroscopy(IR) & FTIR (Analytical Technique)Infrared spectroscopy(IR) & FTIR (Analytical Technique)
Infrared spectroscopy(IR) & FTIR (Analytical Technique)
 
Dispersive & FTIR
Dispersive & FTIRDispersive & FTIR
Dispersive & FTIR
 
Nmr instrumentation Naveen Balaji
Nmr instrumentation Naveen BalajiNmr instrumentation Naveen Balaji
Nmr instrumentation Naveen Balaji
 
UV-VISIBLE SPECTROSCOPY
UV-VISIBLE SPECTROSCOPYUV-VISIBLE SPECTROSCOPY
UV-VISIBLE SPECTROSCOPY
 
FTIR(Fourier transform infrared) spectroscopy
 FTIR(Fourier transform infrared) spectroscopy  FTIR(Fourier transform infrared) spectroscopy
FTIR(Fourier transform infrared) spectroscopy
 
Infrared spectroscopy
Infrared spectroscopyInfrared spectroscopy
Infrared spectroscopy
 
Relaxation in NMR
Relaxation in NMR Relaxation in NMR
Relaxation in NMR
 
IR interpretation and sample handling
 IR interpretation and sample handling  IR interpretation and sample handling
IR interpretation and sample handling
 
INFRARED(IR) SPECTROSCOPY OF NATURAL PRODUCTS
INFRARED(IR) SPECTROSCOPY OF NATURAL PRODUCTSINFRARED(IR) SPECTROSCOPY OF NATURAL PRODUCTS
INFRARED(IR) SPECTROSCOPY OF NATURAL PRODUCTS
 
Interpretation of IR spectra
Interpretation of IR spectraInterpretation of IR spectra
Interpretation of IR spectra
 
Infrared spectroscopy
Infrared spectroscopy Infrared spectroscopy
Infrared spectroscopy
 
Instrumentation of uv spectroscopy
Instrumentation of uv spectroscopyInstrumentation of uv spectroscopy
Instrumentation of uv spectroscopy
 
Nmr spectroscopy
Nmr spectroscopyNmr spectroscopy
Nmr spectroscopy
 
FTIR spectrophotometer
FTIR spectrophotometerFTIR spectrophotometer
FTIR spectrophotometer
 
Uv visible spectroscopy
Uv visible spectroscopyUv visible spectroscopy
Uv visible spectroscopy
 
FTIR spectroscopy
FTIR spectroscopyFTIR spectroscopy
FTIR spectroscopy
 

Similar to IR SPECTROSCOPY

Infrared Spectroscopy_dr bishnu.pdf
Infrared Spectroscopy_dr bishnu.pdfInfrared Spectroscopy_dr bishnu.pdf
Infrared Spectroscopy_dr bishnu.pdfSahabulRayeen
 
IR spectroscopy . P.K.Mani, BCKV, West Bengal, India
IR spectroscopy . P.K.Mani, BCKV, West Bengal,  IndiaIR spectroscopy . P.K.Mani, BCKV, West Bengal,  India
IR spectroscopy . P.K.Mani, BCKV, West Bengal, IndiaP.K. Mani
 
Introduction and applications of FT- IR spectroscopy
Introduction and applications of FT- IR spectroscopyIntroduction and applications of FT- IR spectroscopy
Introduction and applications of FT- IR spectroscopyKANDASAMY K
 
Theory of IR spectroscopy
Theory of IR spectroscopyTheory of IR spectroscopy
Theory of IR spectroscopychiranjibi68
 
Infra Red Spectroscopy for M Sc I (SPPU)
Infra Red Spectroscopy for M Sc I (SPPU)Infra Red Spectroscopy for M Sc I (SPPU)
Infra Red Spectroscopy for M Sc I (SPPU)siraj174
 
6_2018_05_05!06_59_31_PM.ppt
6_2018_05_05!06_59_31_PM.ppt6_2018_05_05!06_59_31_PM.ppt
6_2018_05_05!06_59_31_PM.pptBhupendraShilpi
 
Infrared spectroscopy (vibrational rotational spectroscopy)
Infrared spectroscopy (vibrational rotational spectroscopy)Infrared spectroscopy (vibrational rotational spectroscopy)
Infrared spectroscopy (vibrational rotational spectroscopy)Ravish Yadav
 
Infrared spectroscopy - IR...............
Infrared spectroscopy - IR...............Infrared spectroscopy - IR...............
Infrared spectroscopy - IR...............3611VINODHAVARSHINIS
 
Infrared spectroscopy
Infrared spectroscopy Infrared spectroscopy
Infrared spectroscopy Suvarta Maru
 
null.pptx
null.pptxnull.pptx
null.pptxmineme2
 
Infrared (IR) Spectroscopy
Infrared (IR) SpectroscopyInfrared (IR) Spectroscopy
Infrared (IR) SpectroscopyAshwani Dhingra
 
Basics of Infrared Spectroscopy : Theory, principles and applications
Basics of Infrared Spectroscopy : Theory, principles and applicationsBasics of Infrared Spectroscopy : Theory, principles and applications
Basics of Infrared Spectroscopy : Theory, principles and applicationsHemant Khandoliya
 
irspectroscopy-copy-130904020321-.pdf
irspectroscopy-copy-130904020321-.pdfirspectroscopy-copy-130904020321-.pdf
irspectroscopy-copy-130904020321-.pdfpalaksharma0999
 

Similar to IR SPECTROSCOPY (20)

Infrared Spectroscopy_dr bishnu.pdf
Infrared Spectroscopy_dr bishnu.pdfInfrared Spectroscopy_dr bishnu.pdf
Infrared Spectroscopy_dr bishnu.pdf
 
IR spectroscopy . P.K.Mani, BCKV, West Bengal, India
IR spectroscopy . P.K.Mani, BCKV, West Bengal,  IndiaIR spectroscopy . P.K.Mani, BCKV, West Bengal,  India
IR spectroscopy . P.K.Mani, BCKV, West Bengal, India
 
Infrared spectroscopy
Infrared spectroscopyInfrared spectroscopy
Infrared spectroscopy
 
Introduction and applications of FT- IR spectroscopy
Introduction and applications of FT- IR spectroscopyIntroduction and applications of FT- IR spectroscopy
Introduction and applications of FT- IR spectroscopy
 
Infrared spectroscopy i
Infrared spectroscopy  iInfrared spectroscopy  i
Infrared spectroscopy i
 
Ch 323 INFARED SPECTROSCOPY INTRODUCTION
Ch 323 INFARED SPECTROSCOPY INTRODUCTIONCh 323 INFARED SPECTROSCOPY INTRODUCTION
Ch 323 INFARED SPECTROSCOPY INTRODUCTION
 
Theory of IR spectroscopy
Theory of IR spectroscopyTheory of IR spectroscopy
Theory of IR spectroscopy
 
Electromagnetic radiation
Electromagnetic radiationElectromagnetic radiation
Electromagnetic radiation
 
Infra Red Spectroscopy for M Sc I (SPPU)
Infra Red Spectroscopy for M Sc I (SPPU)Infra Red Spectroscopy for M Sc I (SPPU)
Infra Red Spectroscopy for M Sc I (SPPU)
 
Spectroscopy
SpectroscopySpectroscopy
Spectroscopy
 
6_2018_05_05!06_59_31_PM.ppt
6_2018_05_05!06_59_31_PM.ppt6_2018_05_05!06_59_31_PM.ppt
6_2018_05_05!06_59_31_PM.ppt
 
Infrared spectroscopy (vibrational rotational spectroscopy)
Infrared spectroscopy (vibrational rotational spectroscopy)Infrared spectroscopy (vibrational rotational spectroscopy)
Infrared spectroscopy (vibrational rotational spectroscopy)
 
Ir spectroscopy
Ir spectroscopyIr spectroscopy
Ir spectroscopy
 
Infrared spectroscopy - IR...............
Infrared spectroscopy - IR...............Infrared spectroscopy - IR...............
Infrared spectroscopy - IR...............
 
Infrared spectroscopy
Infrared spectroscopy Infrared spectroscopy
Infrared spectroscopy
 
null.pptx
null.pptxnull.pptx
null.pptx
 
Infrared (IR) Spectroscopy
Infrared (IR) SpectroscopyInfrared (IR) Spectroscopy
Infrared (IR) Spectroscopy
 
Spectroscpoic techniques
Spectroscpoic techniquesSpectroscpoic techniques
Spectroscpoic techniques
 
Basics of Infrared Spectroscopy : Theory, principles and applications
Basics of Infrared Spectroscopy : Theory, principles and applicationsBasics of Infrared Spectroscopy : Theory, principles and applications
Basics of Infrared Spectroscopy : Theory, principles and applications
 
irspectroscopy-copy-130904020321-.pdf
irspectroscopy-copy-130904020321-.pdfirspectroscopy-copy-130904020321-.pdf
irspectroscopy-copy-130904020321-.pdf
 

Recently uploaded

Choosing the Right CBSE School A Comprehensive Guide for Parents
Choosing the Right CBSE School A Comprehensive Guide for ParentsChoosing the Right CBSE School A Comprehensive Guide for Parents
Choosing the Right CBSE School A Comprehensive Guide for Parentsnavabharathschool99
 
Culture Uniformity or Diversity IN SOCIOLOGY.pptx
Culture Uniformity or Diversity IN SOCIOLOGY.pptxCulture Uniformity or Diversity IN SOCIOLOGY.pptx
Culture Uniformity or Diversity IN SOCIOLOGY.pptxPoojaSen20
 
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...Nguyen Thanh Tu Collection
 
Concurrency Control in Database Management system
Concurrency Control in Database Management systemConcurrency Control in Database Management system
Concurrency Control in Database Management systemChristalin Nelson
 
USPS® Forced Meter Migration - How to Know if Your Postage Meter Will Soon be...
USPS® Forced Meter Migration - How to Know if Your Postage Meter Will Soon be...USPS® Forced Meter Migration - How to Know if Your Postage Meter Will Soon be...
USPS® Forced Meter Migration - How to Know if Your Postage Meter Will Soon be...Postal Advocate Inc.
 
ACC 2024 Chronicles. Cardiology. Exam.pdf
ACC 2024 Chronicles. Cardiology. Exam.pdfACC 2024 Chronicles. Cardiology. Exam.pdf
ACC 2024 Chronicles. Cardiology. Exam.pdfSpandanaRallapalli
 
call girls in Kamla Market (DELHI) 🔝 >༒9953330565🔝 genuine Escort Service 🔝✔️✔️
call girls in Kamla Market (DELHI) 🔝 >༒9953330565🔝 genuine Escort Service 🔝✔️✔️call girls in Kamla Market (DELHI) 🔝 >༒9953330565🔝 genuine Escort Service 🔝✔️✔️
call girls in Kamla Market (DELHI) 🔝 >༒9953330565🔝 genuine Escort Service 🔝✔️✔️9953056974 Low Rate Call Girls In Saket, Delhi NCR
 
Judging the Relevance and worth of ideas part 2.pptx
Judging the Relevance  and worth of ideas part 2.pptxJudging the Relevance  and worth of ideas part 2.pptx
Judging the Relevance and worth of ideas part 2.pptxSherlyMaeNeri
 
Student Profile Sample - We help schools to connect the data they have, with ...
Student Profile Sample - We help schools to connect the data they have, with ...Student Profile Sample - We help schools to connect the data they have, with ...
Student Profile Sample - We help schools to connect the data they have, with ...Seán Kennedy
 
Virtual-Orientation-on-the-Administration-of-NATG12-NATG6-and-ELLNA.pdf
Virtual-Orientation-on-the-Administration-of-NATG12-NATG6-and-ELLNA.pdfVirtual-Orientation-on-the-Administration-of-NATG12-NATG6-and-ELLNA.pdf
Virtual-Orientation-on-the-Administration-of-NATG12-NATG6-and-ELLNA.pdfErwinPantujan2
 
Science 7 Quarter 4 Module 2: Natural Resources.pptx
Science 7 Quarter 4 Module 2: Natural Resources.pptxScience 7 Quarter 4 Module 2: Natural Resources.pptx
Science 7 Quarter 4 Module 2: Natural Resources.pptxMaryGraceBautista27
 
Inclusivity Essentials_ Creating Accessible Websites for Nonprofits .pdf
Inclusivity Essentials_ Creating Accessible Websites for Nonprofits .pdfInclusivity Essentials_ Creating Accessible Websites for Nonprofits .pdf
Inclusivity Essentials_ Creating Accessible Websites for Nonprofits .pdfTechSoup
 
AUDIENCE THEORY -CULTIVATION THEORY - GERBNER.pptx
AUDIENCE THEORY -CULTIVATION THEORY -  GERBNER.pptxAUDIENCE THEORY -CULTIVATION THEORY -  GERBNER.pptx
AUDIENCE THEORY -CULTIVATION THEORY - GERBNER.pptxiammrhaywood
 
AMERICAN LANGUAGE HUB_Level2_Student'sBook_Answerkey.pdf
AMERICAN LANGUAGE HUB_Level2_Student'sBook_Answerkey.pdfAMERICAN LANGUAGE HUB_Level2_Student'sBook_Answerkey.pdf
AMERICAN LANGUAGE HUB_Level2_Student'sBook_Answerkey.pdfphamnguyenenglishnb
 
ENGLISH6-Q4-W3.pptxqurter our high choom
ENGLISH6-Q4-W3.pptxqurter our high choomENGLISH6-Q4-W3.pptxqurter our high choom
ENGLISH6-Q4-W3.pptxqurter our high choomnelietumpap1
 
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)lakshayb543
 
ENGLISH 7_Q4_LESSON 2_ Employing a Variety of Strategies for Effective Interp...
ENGLISH 7_Q4_LESSON 2_ Employing a Variety of Strategies for Effective Interp...ENGLISH 7_Q4_LESSON 2_ Employing a Variety of Strategies for Effective Interp...
ENGLISH 7_Q4_LESSON 2_ Employing a Variety of Strategies for Effective Interp...JhezDiaz1
 

Recently uploaded (20)

LEFT_ON_C'N_ PRELIMS_EL_DORADO_2024.pptx
LEFT_ON_C'N_ PRELIMS_EL_DORADO_2024.pptxLEFT_ON_C'N_ PRELIMS_EL_DORADO_2024.pptx
LEFT_ON_C'N_ PRELIMS_EL_DORADO_2024.pptx
 
Choosing the Right CBSE School A Comprehensive Guide for Parents
Choosing the Right CBSE School A Comprehensive Guide for ParentsChoosing the Right CBSE School A Comprehensive Guide for Parents
Choosing the Right CBSE School A Comprehensive Guide for Parents
 
Culture Uniformity or Diversity IN SOCIOLOGY.pptx
Culture Uniformity or Diversity IN SOCIOLOGY.pptxCulture Uniformity or Diversity IN SOCIOLOGY.pptx
Culture Uniformity or Diversity IN SOCIOLOGY.pptx
 
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
HỌC TỐT TIẾNG ANH 11 THEO CHƯƠNG TRÌNH GLOBAL SUCCESS ĐÁP ÁN CHI TIẾT - CẢ NĂ...
 
Concurrency Control in Database Management system
Concurrency Control in Database Management systemConcurrency Control in Database Management system
Concurrency Control in Database Management system
 
USPS® Forced Meter Migration - How to Know if Your Postage Meter Will Soon be...
USPS® Forced Meter Migration - How to Know if Your Postage Meter Will Soon be...USPS® Forced Meter Migration - How to Know if Your Postage Meter Will Soon be...
USPS® Forced Meter Migration - How to Know if Your Postage Meter Will Soon be...
 
ACC 2024 Chronicles. Cardiology. Exam.pdf
ACC 2024 Chronicles. Cardiology. Exam.pdfACC 2024 Chronicles. Cardiology. Exam.pdf
ACC 2024 Chronicles. Cardiology. Exam.pdf
 
call girls in Kamla Market (DELHI) 🔝 >༒9953330565🔝 genuine Escort Service 🔝✔️✔️
call girls in Kamla Market (DELHI) 🔝 >༒9953330565🔝 genuine Escort Service 🔝✔️✔️call girls in Kamla Market (DELHI) 🔝 >༒9953330565🔝 genuine Escort Service 🔝✔️✔️
call girls in Kamla Market (DELHI) 🔝 >༒9953330565🔝 genuine Escort Service 🔝✔️✔️
 
Judging the Relevance and worth of ideas part 2.pptx
Judging the Relevance  and worth of ideas part 2.pptxJudging the Relevance  and worth of ideas part 2.pptx
Judging the Relevance and worth of ideas part 2.pptx
 
Student Profile Sample - We help schools to connect the data they have, with ...
Student Profile Sample - We help schools to connect the data they have, with ...Student Profile Sample - We help schools to connect the data they have, with ...
Student Profile Sample - We help schools to connect the data they have, with ...
 
Virtual-Orientation-on-the-Administration-of-NATG12-NATG6-and-ELLNA.pdf
Virtual-Orientation-on-the-Administration-of-NATG12-NATG6-and-ELLNA.pdfVirtual-Orientation-on-the-Administration-of-NATG12-NATG6-and-ELLNA.pdf
Virtual-Orientation-on-the-Administration-of-NATG12-NATG6-and-ELLNA.pdf
 
Raw materials used in Herbal Cosmetics.pptx
Raw materials used in Herbal Cosmetics.pptxRaw materials used in Herbal Cosmetics.pptx
Raw materials used in Herbal Cosmetics.pptx
 
Science 7 Quarter 4 Module 2: Natural Resources.pptx
Science 7 Quarter 4 Module 2: Natural Resources.pptxScience 7 Quarter 4 Module 2: Natural Resources.pptx
Science 7 Quarter 4 Module 2: Natural Resources.pptx
 
Inclusivity Essentials_ Creating Accessible Websites for Nonprofits .pdf
Inclusivity Essentials_ Creating Accessible Websites for Nonprofits .pdfInclusivity Essentials_ Creating Accessible Websites for Nonprofits .pdf
Inclusivity Essentials_ Creating Accessible Websites for Nonprofits .pdf
 
AUDIENCE THEORY -CULTIVATION THEORY - GERBNER.pptx
AUDIENCE THEORY -CULTIVATION THEORY -  GERBNER.pptxAUDIENCE THEORY -CULTIVATION THEORY -  GERBNER.pptx
AUDIENCE THEORY -CULTIVATION THEORY - GERBNER.pptx
 
AMERICAN LANGUAGE HUB_Level2_Student'sBook_Answerkey.pdf
AMERICAN LANGUAGE HUB_Level2_Student'sBook_Answerkey.pdfAMERICAN LANGUAGE HUB_Level2_Student'sBook_Answerkey.pdf
AMERICAN LANGUAGE HUB_Level2_Student'sBook_Answerkey.pdf
 
ENGLISH6-Q4-W3.pptxqurter our high choom
ENGLISH6-Q4-W3.pptxqurter our high choomENGLISH6-Q4-W3.pptxqurter our high choom
ENGLISH6-Q4-W3.pptxqurter our high choom
 
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)
Visit to a blind student's school🧑‍🦯🧑‍🦯(community medicine)
 
FINALS_OF_LEFT_ON_C'N_EL_DORADO_2024.pptx
FINALS_OF_LEFT_ON_C'N_EL_DORADO_2024.pptxFINALS_OF_LEFT_ON_C'N_EL_DORADO_2024.pptx
FINALS_OF_LEFT_ON_C'N_EL_DORADO_2024.pptx
 
ENGLISH 7_Q4_LESSON 2_ Employing a Variety of Strategies for Effective Interp...
ENGLISH 7_Q4_LESSON 2_ Employing a Variety of Strategies for Effective Interp...ENGLISH 7_Q4_LESSON 2_ Employing a Variety of Strategies for Effective Interp...
ENGLISH 7_Q4_LESSON 2_ Employing a Variety of Strategies for Effective Interp...
 

IR SPECTROSCOPY

  • 1. INFRARED SPECTROSCOPY THEORY PRESENTED BY: ANUPAMA RAMACHANDRAN 1st Year M Pharm Pharmacology 1
  • 2. CONTENTS • INTRODUCTION • IR SPECTROSCOPY • PRINCIPLE • MOLECULAR VIBRATIONS • COUPLED INTERACTIONS • DEGREE OF FREEDOM • SUMMARY • REFERENCE 2
  • 3. INTRODUCTION • Spectroscopy is the measurement and interpretation of EMR absorbed or emitted when the molecules or atoms or ions of a sample moves from one energy state to another energy state. • Spectroscopy is an instrumentally aided study of the interactions between matter (sample being analyzed) and energy (any portion of the electromagnetic spectrum) 3
  • 4. SPECTROSCOPY ABSORPTION SPECTROSCOPY EMISSION SPECTROSCOPY *UV SPECTROSCOPY * FLUORIMETRY *IR SPECTROSCOPY * FLAME PHOTOMETRY *NMR SPECTROSCOPY 4
  • 5. IR SPECTROSCOPY • Energy of molecule = Electronic energy+ Vibrational energy + Rotational energy • IR spectroscopy is concerned with the study of absorption of infrared radiation, which causes vibrational transition in the molecule. Hence, IR spectroscopy also known as Vibrational spectroscopy. • IR spectra mainly used in structure elucidation to determine the functional groups. 5
  • 6. 6
  • 7. IR REGION: 0.8 µm (800nm) to 1000 µm (1mm) subdivided into 1.Near IR: 0.8-2 µm 2.Middle IR: 2-15 µm 3.Far IR: 15-1000 µm Most of the analytical applications are confined to the middle IR region because absorption of organic molecules are high in this region. 7
  • 8. • GROUP FREQUENCY REGION:( 4000 to 1500 cm-1) Contain relatively few peaks. Associated with stretching vibrations. Almost all the stretching vibrations are above 1450 cm-1. IR stretching frequencies 8
  • 9. FINGER PRINT REGION: (1500 – 400 cm-1 ) • Usually consist of bending vibrations within the molecule. • pattern of peaks are more complicated & is much difficult pickout individual bonds in this region • Each compound produce its own unique pattern of peaks like a finger print in this region . 9
  • 10. • In pharmaceutical analysis, infrared radiation (mid IR) of wavelength 25µ to 2.5µ or wave numbers from 400cm-1 to 4000 cm-1. • we use wave no. instead of wave length for mentioning characteristic peak ,because wave numbers are larger values & easy to handle than wave lengths. • Wave no: no. of waves present per cm • 1 𝑤𝑎𝑣𝑒𝑙𝑒𝑛𝑔𝑡ℎ 𝑖𝑛 𝜇 × 104 = wave no. per cm 10
  • 11. • Molecules are made up of atoms linked by chemical bonds. The movement of atoms and the chemical bonds is like spring and balls (vibration). • This characteristic vibration are called Natural frequency of vibration. PRINCIPLE OF IR SPECTROSCOPY 11
  • 12. • When energy in the form of infrared radiation is applied ,then it causes vibration between the atoms of the molecules and when, Applied infrared frequency = Natural frequency of vibration Then, Absorption of IR radiation takes place and a peak is observed. Different functional groups absorb characteristic frequencies of IR radiation. Hence gives the characteristic peak value. Therefore, IR spectrum of a chemical substance is a finger print of a molecule for its identification. 12
  • 13. CRITERIA FOR A COMPOUND TO ABSORB IR RADIATION • 1. Correct wavelength of radiation • 2. Change in dipole moment 1. Correct wavelength of radiation: A molecule to absorb IR radiation, the natural frequency of vibrations of some part of a molecule is the same as the frequency of incident radiation. 13
  • 14. 2. Change in dipole moment • A molecule can only absorb IR radiation when its absorption cause a change in its electric dipole • A molecule is said to have an electric dipole when there is a slight positive and a slight negative charge on its component of atoms. 14
  • 15. MOLECULAR VIBRATIONS • Any change in shape of the molecule. 2 types, 1) fundamental vibrations 2) non fundamental vibrations 15
  • 16. FUNDAMENTAL VIBRATIONS There are 2 types of vibrations: 1.Stretching vibrations 2.Bending vibrations 16
  • 17. 1.STRETCHING VIBRATIONS:  Vibration or oscillation along the line of bond Change in bond length  Occurs at higher energy: 4000-1250 cm-1 2 types: a)Symmetrical stretching b)Asymmetrical stretching 17
  • 18. a) Symmetrical stretching: • 2 bonds increase or decrease in length simultaneously. 18
  • 20. b) Asymmetrical stretching: • in this, one bond length is increased and other is decreased 20
  • 22. 2. BENDING VIBRATIONS  Vibration or oscillation not along the line of bond  These are also called as deformations  In this, bond angle is altered  Occurs at low energy: 1400-666 cm-1  2 types: a) In plane bending: scissoring, rocking b) Out plane bending: wagging, twisting 22
  • 23. a) In plane bending i. Scissoring: • This is an in plane bending • 2 atoms approach each other • Bond angles are decreased 23
  • 25. ii. Rocking: • Movement of atoms take place in the same direction. 25
  • 27. b) Out plane bending i. Wagging: • 2 atoms move to one side of the plane. • They move up and down the plane. 27
  • 29. ii. Twisting: • One atom moves above the plane and another atom moves below the plane. 29
  • 31. COUPLED INTERACTIONS • Interactions between vibrations can occur (Coupling) if the vibrating bonds are joined to a single, central atom. • This is because there is mechanical coupling interaction between the oscillators. Example: C=O (both symmetric and asymmetric stretching vibrations) 31
  • 32. REQUIREMENTS FOR COUPLING • The vibrations must be of the same symmetry species if interaction is to occur. • Strong coupling of stretching vibrations occurs when there is a common atom between the two vibrating bonds. • Coupling of bending vibrations occur when there is a common bond between vibrating groups. 32
  • 33. • Coupling is greatest when the coupled groups have approximately equal energies. • Coupling between a stretching vibration and a bending vibration occurs if the stretching bond is one side of an angle varied by bending vibration. • No coupling is seen between groups separated by two or more bonds 33
  • 34. 34
  • 35. FACTORS AFFECTING FREQUENCY OF IR ABSORPTION • Relative mass of the atom. • Force constant of the bonds. • Geometry of the atom. 35
  • 36. DEGREE OF FREEDOM • Fundamental vibration of molecule depend on degree of freedom. • Each atom has 3 degree of freedom depend on x, y, z. • For a molecule containing n no. of atoms has 3n degree of freedom. • For non – linear molecule, 3 degree of freedom represent rotational & transational motion. • For non-linear, ( 3n -6) degree of freedom represent fudamental vibrations. • For linear (3n-5) degree of freedom represent fundamental vibrations. • All vibrational changes don’t appear as band. • Only those vibrational changes that result in change in dipole moment appear as band. 36
  • 38. 38
  • 39. SUMMARY • Absorption spectroscopy. • Vibrational transitions. • Applied infrared frequency = Natural frequency of vibration. • Structure elucidation to determine functional groups. 39
  • 40. REFERENCES 1. Spectrometric identification of organic compounds, sixth edition, Robert M. Silverstein & Francis X. Webster. Page no: 71 – 76 2. Principles of instrumental analysis, 6th edition, Douglas A. Skoog , E James Holler, Stanley R Crouch . Page no: 430 – 455 3. Introduction to spectroscopy, Donald L Pavia, Gary M. Lampman, James R. Vyvyan. Page no: 15 - 31 40