book

Molecular Spectrocopy,1e

Name: Molecular Spectrocopy,1e
Author: S.K. Dogra
ISBN: 9789332540811

by S.K. Dogra

July 2014

Intermediate to advanced

784 pages

24h 35m

English

Pearson Education India

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Cover
Title Page
Brief Contents
Contents
Preface
About the Authors
1. Introduction
1.1 Spectroscopy1.2 Nature of Electromagnetic Radiations1.3 Characteristics of Electromagnetic Radiations and Atoms/Molecules1.4 Born-Oppenheimer Approximation1.5 Schrödinger Wave Equation1.6 General Condition of Resonance, i.e. Absorption or Emission1.7 Molecular Spectroscopy and Spectral Regions1.8 Spectrum and Basic Elements of a Single and Double Beam Absorption Spectrometer1.8.1 Signal to Noise Ratio1.8.2 Resolving Power of a Spectrometer and Its Relation to Slit Width1.8.3 Width of the Spectral Lines and Factors Affecting It1.9 Intensity of the Spectral Bands (or Quantum Mechanical Treatment of Transition Between Two States)1.9.1 The Transition Probability1.9.2 Boltzmann Distribution Law and Population in Energy States1.9.3 Average Lifetime of the Excited State1.9.4 Concentration and Path Length of Sample1.10 Limit of Sensitivity of the Spectroscopic Method of Identification of Substances1.11 Fourier Transform (FT) and Computer Average Transient (CAT)1.12 Fitting of a Straight Line and Method of Least SquaresProblemsAppendix A-1.1
2. Atomic Structure and Atomic Spectra
2.1 Introduction2.2 History and Experimental Results of Atomic Spectrum2.2.1 Experimental Evidence for the Existence of Excited Levels in the Atom2.2.2 Spectra of Alkali Metals2.3 Quantum Mechanical Model of Atom2.3.1 Hydrogen Atom2.4 Fine (Multiplet) Structure of Atomic Terms (States)2.4.1 Atom (Ion) with One Outer Electron2.4.2 Fine Structure of the Terms of an Atom (Ion) with Two Outer Electrons2.4.3 Designations (Fuller Characterisation) of Atomic Terms2.4.4 Terms of Atoms with Any Number of Electrons2.5 Hyperfine Structure of Spectral Terms2.5.1 Lande Interval Rule2.6 Genesis of the Periodic System of Elements2.7 Intensity of Spectral Lines2.7.1 Selection Rules2.7.2 Breakdown of Selection Rules2.7.3 Intensity Rules2.8 Atomic Spectra2.8.1 Atomic Spectrum of Hydrogen Atom2.8.2 Atomic Spectra of Alkali Elements (One-Electron System)
2.8.3 Spectrum of Helium Atom (Two-Electron System)
2.8.4 Spectrum of Mercury Atom (Two Electron System)2.9 An Atom in Magnetic Field2.9.1 Normal Zeeman Effect2.9.2 Anomalous Zeeman Effect2.9.3 Paschen–Back Effect2.9.4 Breakdown of ΔS = 0 Selection Rule and the Paschen–Back Effect2.10 An Atom in Electric Field (Stark Effect)2.10.1 Linear Stark Effect (Hydrogen Atom)Problems
3. Rotational Spectrum
3.1 Introduction3.2 Rotational Motion of Dumbbell-Shaped Species (or Diatomic Molecule as Rigid Rotator)3.3 Quantum Restrictions on Rotation of Diatomic Molecule3.3.1 Rotational Angular Momentum3.3.2 Rotational Energy Levels3.4 Rotational Spectrum and Bond Lengths of Diatomic Molecules3.5 Interaction of Radiation with Molecule3.6 Spectrum3.7 Thermal Distribution of Rotational Quantum States (Intensities of the Rotational Lines)3.8 Limitations of Simple Model3.8.1 Effect of Isotopes on the Rotational Spectrum3.8.2 Non-Rigid Rotator3.8.3 Effect of Nuclear Spin (Hyperfine Structure)3.9 Polyatomic Molecules3.9.1 Polyatomic Linear Molecules3.9.2 Energy Levels and Spectra3.9.3 Rotational Spectra of Spherical Top Molecules3.9.4 Rotational Spectra of Symmetric Top Molecules3.9.5 Transition Between Two Adjacent Energy States (Prolate/Oblate Tops as Rigid Rotators)3.9.6 Rotational Spectra of Asymmetric Top Molecules3.10 Microwave Spectrometer3.11 Stark Effect in Relation to Dipole Moment Determination from Rotational Spectrum3.12 Applications of Microwave Spectroscopy3.12.1 Microwave OvenProblems

4. Vibrational Spectra and the Flexibility of Molecules
4.1 Introduction4.2 Vibration of a Ball and Spring System4.3 Vibrational Energy Levels of Diatomic Molecule4.3.1 The Simple Harmonic Oscillator4.3.2 Wave Functions of Harmonic Oscillator4.3.3 Mechanism of Absorption of Infrared Radiation by Molecules4.3.4 Spectrum4.3.5 Intensity or Thermal Population Distribution4.4 The Anharmonic Oscillator4.4.1 Energy Levels4.4.2 Spectrum4.5 Hot Vibrational Bands4.6 Rotational-Vibrational Spectrum4.6.1 Energy Levels4.6.2 Selection Rules4.6.3 Rotational-Vibrational Spectrum4.6.4 Calculation of the Rotational Constants4.7 Dissociation Energy of Diatomic Molecules4.7.1 Maximum Value of Vibrational Quantum Number and Energy4.7.2 Bond Energy of Diatomic Molecule4.7.3 Determination of Dissociation Energy of Diatomic Molecules4.8 Nature and Number of Vibrational Motions in Polyatomic Molecules4.8.1 Number of Vibrations and their Symmetry4.8.2 Overtones and Combination Bands4.8.3 Fermi Resonance4.8.4 Vibrational Coupling4.8.5 Rotation-Vibration Spectra of Polyatomic Molecules4.9 Basic Principles of a Double Beam Dispersive Infrared Spectrometer4.9.1 Basic Principles of Fourier Transform Infrared Spectrometer (FTIRS)
4.10 Qualitative Applications of Infrared Spectroscopy
4.10.1 Structural Elucidation4.10.2 Identification of Molecular Species4.10.3 Study of Environmental Effects of Molecular Systems4.10.4 Study of Briged Inorganic ComplexesProblemsAppendix 4A-1
5. Raman Spectroscopy
5.1 Introduction5.2 Classical Theory of Raman Scattering5.2.1 Geometrical Description of Three Dimensional Polarizability5.2.2 Vibrational and Rotational Raman Spectrum5.3 Quantum Theory of Raman Scattering5.4 General Selection Rule for Raman Scattering5.4.1 Based on Polarizability5.4.2 Mutual Exclusion Principle5.5 Raman Spectra of Diatomic Molecules5.5.1 Pure Rotational Raman Spectra of Diatomic Molecules5.5.2 Vibrational Raman Spectra of Diatomic Molecules5.5.3 Rotational-Vibrational Raman Spectra of Diatomic Molecules5.6 Vibrational Raman Spectra of Polyatomic Molecules5.7 Basic Principles of a Raman Spectrometer5.8 Resonance Raman Scattering/Effect (RRS/RRE)5.9 Applications of Raman Spectroscopy5.9.1 Study of Environmental Effects on Molecular Systems5.9.2 Mechanism of Tautomerism and Polymerisation5.9.3 Nature of Chemical Bond5.9.4 Molecular StructureProblems
6. Electronic Spectrum
6.1 Introduction6.2 Diatomic Molecules6.2.1 Bonding in Diatomic Molecules6.2.2 The Shapes of the Molecular Orbitals in Diatomic Molecules6.2.3 Energies of m.o.’s6.2.4 Electronic Configuration of A2 Molecules6.3 Classification of Electronic States6.3.1 Orbital Angular Momentum6.3.2 Spin Angular Momentum6.3.3 Total Angular Momentum6.3.4 Symmetry Properties of the Electronic Wave Functions or Orbitals6.3.5 Term Symbols6.4 Stable and Unstable States6.5 Electronic Spectrum of Diatomic Molecules6.5.1 Born–Oppenheimer Approximation6.5.2 Coarse or Vibrational Structure of Electronic Transitions6.5.3 Rotational Structure (or Finer Details) of Electronic Bands6.6 The Isotope Effect in Molecular Electronic Spectra6.6.1 Vibrational Isotope Effect6.6.2 Rotational Isotope Effect6.7 Continuous Absorption and Emission Spectra6.7.1 Absorption6.8 Pre-dissociation/Diffuse Spectra6.8.1 Mechanism of Pre-dissociation in Diatomic Molecules6.8.2 Pre-dissociation in Polyatomic Molecules6.8.3 Pre-dissociation in Emission Spectra6.9 Dissociation Energy and Its Determination6.9.1 Band Convergence Method6.9.2 Pre-dissociation Limit Method
6.10 Electronic Spectrum of Polyatomic Molecules
6.10.1 The Concept of Chromophore6.10.2 Nature of Molecular Orbitals6.10.3 Electronic Spectra of Different Chromophores6.10.4 Multiple Bond6.10.5 The Multiple-Bonded Basic Group6.10.6 Aromatic Systems6.11 Structure and Spectra of Transition Metal Complexes6.11.1 Ligand Field Theory (LFT)6.11.2 Different Kinds of Absorption Transitions6.11.3 Experimental Examples and Comparing Them with States Arising from Electronic Configuration Using LFT6.11.4 Energy Level Diagrams6.12 Deactivation of Excited States6.12.1 Non-Radiative Processes6.12.2 Radiative Processes6.13 Basic Principles of a Double Beam UV-Visible Spectrophotometer6.14 Applications of Low Resolution UV–Visible Spectroscopy6.14.1 Qualitative AnalysisProblemsAppendix 6A
7. Nuclear Magnetic Resonance Spectroscopy
7.1 Nuclear Properties Relevant to Nuclear Magnetic Resonance (NMR)7.2 Concept of Nuclear Magnetic States7.3 Units of Some Magnetic Properties Involved in NMR7.4 Energy of the Magnetic States7.5 Larmor Theorem7.6 General Selection Rules for the Transition Between Magnetic States7.7 The Magnetic Resonance Condition7.8 Equivalence of Classical Larmor Precessional Frequency and Quantum Mechanical Transition Frequency7.9 Nuclear Population in Different States7.10 Line Shape and Line Width7.11 Intensity of NMR Signal7.12 Spin Relaxation Process7.12.1 Types of Relaxation Processes7.12.2 Width of NMR Signal and Relaxation Times7.13 Fourier Transform NMR (FTNMR) Spectroscopy7.14 The Screening Constant (σ)7.14.1 Chemical Shift Scale7.14.2 Standard Reference and Chemical Shift of Some Other Nuclei7.15 Effects of Chemical Environments on Chemical Shift7.16 Dipole-Dipole (d-d )- and Spin-Spin (s-s) Coupling7.17 Concept of Chemical-Shift Equivalent and Magnetically Equivalent Protons7.17.1 Chemical-Shift Equivalent Protons7.17.2 Magnetically Equivalent Protons7.18 Quantification (Mechanism) of s–s Interaction7.19 NMR Spectrometers7.19.1 Basic Principles of NMR Spectrometer7.20 Simplification of NMR Spectrum7.20.1 NMR Spectrometers with Higher Magnetic Field Strength7.20.2 Use of Chemical Shift Reagents7.20.3 Deuteration7.20.4 Double Resonance Experiment7.20.5 Spin Decoupling7.20.6 Basic Principle of a Fourier Transform NMR (FTNMR) Spectrometer7.21 13C-NMR Spectroscopy7.22 Applications7.22.1 The Structural Elucidation7.22.2 Analytical ApplicationProblems
8. Electron Spin Resonance Spectroscopy
8.1 Introduction8.2 Similarities Between ESR and NMR8.3 Energy of Free-Electron Spin State8.4 Energy Levels of a Free Electron in an External Magnetic Field8.5 Intensity of ESR Lines and Factors Affecting It8.6 Relaxation Processes8.6.1 Spin–Lattice Relaxation8.6.2 s–s Interactions8.7 ESR Line Width and Factors Affecting It8.8 g-Value and Factors Affecting ESR Lines8.9 Zero-Field Splitting (Fine Structure Terms) and Kramer’s Degeneracy8.10 Hyperfine Interaction8.11 Types of Hyperfine Interactions8.11.1 Isotropic Hyperfine Interaction8.12 Rules for the Prediction of Number of Hyperfine Lines and their Relative Intensities: Analysis of Isotropic EPR Spectra8.12.1 Analysis for Equivalent Nuclei8.13 Basic Principle of an ESR Spectrometer8.14 Fourier Transform ESR Spectroscopy (FTESRS)8.15 Applications of ESR Spectroscopy8.15.1 Determination of Concentration of Free Radicals8.15.2 Determination of Unpaired Electron Spin Density and the Molecular Shape of Free RadicalProblems
9. Mössbauer Spectroscopy
9.1 Introduction9.2 Isomer Nuclear Transitions9.3 Resonance Fluorescence9.3.1 Atomic Resonance Fluorescence9.3.2 Nuclear Gamma Ray Resonance Fluorescence9.4 Mössbauer Effect9.4.1 Line Position9.4.2 Intensity of Mössbauer Line and Parameters Affecting It9.4.3 Width of Mössbauer Line and Factors Affecting It9.5 Hyperfine Interactions9.5.1 Centre Shift9.5.2 Nuclear Isomer Shift and Factors Affecting It9.6 Magnetic Hyperfine Structure9.6.1 Internal or Effective Magnetic Field9.6.2 Effect of External Magnetic Field (or Magnetic Hyperfine Interactions)9.7 Electric Quadrupole Interaction9.7.1 Intensity of Nuclear Quadrupole Doublet9.7.2 Magnitude and Sign of Quadrupole Interaction9.7.3 Effect of Combination of Magnetic and Quadrupole Interactions9.8 Mössbauer Spectrometer9.8.1 Mössbauer Spectrum9.8.2 Data Computation9.9 Applications of Mössbauer Spectroscopy9.9.1 Structure of Coordination Compounds9.9.2 Catalysis: Tin Dioxide Assisted Antimony Oxidation9.9.3 Off-Centre Tin Atoms in PbSnTeSe9.9.4 Uranium/Iron Multilayers9.9.5 Superspin Glass Transition in Al49Fe30Cu219.9.6 Spin-State EquilibriaProblems
10. Lasers
10.1 Introduction10.2 Stimulated Absorption10.2.1 Spontaneous Emission10.3 Stimulated Emission10.4 Relations Between the Einstein’s Coefficients10.5 Idea of Lasing Action10.6 Methods to Create Population Inversion10.7 Principle of Pumping Schemes10.8 Requirements and Rate Equations for Lasers10.8.1 A Two-Level System10.8.2 A Three-Level System10.8.3 A Four-Level Laser System10.9 Experimental Aspect of Lasers10.9.1 Optically Resonance Cavity10.9.2 Characteristics of Optical Resonate Cavity10.9.3 Radiant Losses10.9.4 Diffraction Losses10.9.5 Stable and Unstable Resonators10.10 Characteristics of Laser Beams10.10.1 Monochromaticity10.10.2 Coherence10.10.3 Directionality10.10.4 Brightness10.10.5 Stimulated Radiation and Emitted Radiation10.11 Methods of Q-Switching10.11.1 Mechanism of Bleaching10.12 Wavelength Range and Power Output of Lasers10.13 Few Specific Laser Systems10.13.1 Solid-State Lasers10.13.2 Ion and Atomic Lasers10.13.3 Molecular Lasers10.13.4 Liquid Lasers10.13.5 Electroionisation Lasers (High Pressure Gas Lasers)10.13.6 Gas-Dynamic Lasers10.13.7 Chemical Lasers10.13.8 Chain Reactions for Chemical Lasers10.13.9 Plasma Lasers: Recombination Plasma as the Active Medium10.13.10 Semi-conductor Lasers10.13.11 Injection Lasers10.13.12 Photodissociation Lasers10.14 Applications of Lasers10.14.1 Laser Spectroscopy10.14.2 Isotope Separation10.14.3 Environmental Studies10.14.4 Holography10.14.5 Engineering Applications10.14.6 Lasers in Chemical Kinetics10.14.7 Lasers in MedicinesProblemsAppendix 10-A
11. Mass Spectrometry
11.1 Introduction11.2 Comparison of Mass Spectrometry with Other Spectroscopic Techniques11.3 Basic Principles of Mass Spectrometry11.3.1 Electron Impact Mass Spectrometry11.4 Presentation of Mass Spectrum11.5 Parameters of Good Mass Spectrometer11.5.1 Resolving Power or Resolution of a Mass Spectrometer11.5.2 Mass Spectrometer Sensitivity11.6 Various Forms of Mass Spectrometry on the Basis of Ionisation Processes Other Than EIMS11.6.1 Chemical Ionisation Mass Spectrometry (CIMS)11.6.2 Fast Atom Bombardment Mass Spectrometry (FABMS)11.7 Various Types of Ions Enclosed in Mass Spectrometry11.7.1 Parent or Original Molecular Ion11.7.2 Fragment Ions11.7.3 Multi-charged Ions11.7.4 Metastable Ions11.7.5 Negative Ions11.8 Intensities of the Signals in the Mass Spectrum11.9 Intensity of the Parent Peak and Factors Affecting it11.10 Terms and Symbols Used for the Mode of Fragmentation of Molecular Ions11.11 General Rules for Writing Molecular Formula11.11.1 Hydrogen Rule11.11.2 Nitrogen Rule11.11.3 Ring Rule11.11.4 Even-Electron Rule11.12 Mode of Fragmentation of Positively Charged Molecular Ion11.12.1 Ordinary Fissions11.12.2 Hydrocarbons11.12.3 Alkenes11.12.4 Saturated Ring Systems11.12.5 Compound with Cyclic Double Bond11.12.6 Aromatic and Aralkyl Hydrocarbons11.12.7 Rupture of a Bond Close to Negative Atom (Electronegative Atom)11.13 Elimination of Neutral Molecules11.14 Rearrangement Fissions11.14.1 Hydrogen-Migration via Six Member Transition (McLafferty Rearrangement)11.15 Interpretation of Mass Spectra of Unkown Compounds11.16 Applications of Mass Spectrometry11.16.1 Determination of Atomic Masses of Elements11.16.2 Identification of Molecular Species from Fragmentation Pattern11.16.3 Determination of Molecular Formula11.16.4 Beynon Method for Computation of Abundance ParametersProblems
Bibliography
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Content preview from Molecular Spectrocopy,1e

2.8.3 Spectrum of Helium Atom (Two-Electron System)

After one-electron atoms, the spectrum of helium is the simplest to study. Helium atom contains two valence electrons (1s²) and total binding energy of He-atom is 78.98 eV. The energy levels and the observed emission spectrum of He-atom are shown in Figure 2.20. The energy levels and spectrum results due to excitation of one of the two 1s electrons while the state of the second 1s electron is held constant. The lines in the emission spectrum fall into two distinct sets of hydrogen like series, which are quite independent of each other. The earlier workers thought that these two distinct and independent sets of series belong to two different types of helium christened by them ortho- and parahelium. ...

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Molecular Spectrocopy,1e

by S.K. Dogra

2.8.3 Spectrum of Helium Atom (Two-Electron System)

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