Spectroscopy. Practical Handbook of. J. W. Robinson, Ph.D., D.Sc, F.R.C.S. Department of Chemistry Louisiana State University Baton Rouge, Louisiana

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1 Practical Handbook of Spectroscopy Edited by J. W. Robinson, Ph.D., D.Sc, F.R.C.S. Department of Chemistry Louisiana State University Baton Rouge, Louisiana CRC Press Boca Raton Ann Arbor Boston

2 TABLE OF CONTENTS SECTION 1. X-RAY SPECTROSCOPY X-Ray Spectroscopy 3 I. Characteristic X-Ray Emission Lines 3 Table 1 Wavelength, Probable Error in Last Digit of Wavelength, and Energy of Some Characteristic Emission Lines 4 References 22 IL Characteristic X-Ray Absorption Edges 23 Table 2 X-Ray Absorption Edges 24 References 27 III. Mass Attenuation and Absorption Cross Sections for 94 Elements; 0.1 kev to 1 MeV 28 Table 3 Mass Attenuation and Absorption Cross Sections for 94 Elements; 0.1 kev to 1 MeV 28 IV. Approximate Jump Factors for K and L Absorption Edges 155 Table 4 K-Edge Jump Factors 155 Table 5 L-Edge Jump Factors 155 V. Schematic Energy Level Diagram Showing the X-Ray Lines 156 VI. Crystals and Multilayer Langmuir-Blodgett Films Used as Analyzers in Wavelength-Dispersive X-Ray Spectrometers 157 Table 6 Crystals and Multilayer Langmuir-Blodgett Films Used as Analyzers in Wavelength-Dispersive X-Ray Spectrometers 158 VII. Cross Sections for lonization of K- and L-Shells by Electrons 167 VIII. Electron Range and Electron Stopping Power 168 Table 7A The Stopping Power for Electrons of Energy V in Targets of Atomic Number Z 169 Table 7B The Stopping Power for Electrons of Energy V in Targets of Atomic Number Z 170 Table 8 The Mass-Range ps (g/cm 2 ) at which the Electron Energy Has Fallen from Its Initial Energy, V 0, to the K-Shell lonization Energy in Targets of Atomic Number Z 171 Table 9 The Mass-Range ps (g/cm 2 ) at which the Electron Energy Has Fallen from Its Initial Energy, V 0, to the L m -Shell lonization Energy in Targets of Atomic Number Z 172 SECTION 2. ESCA PHOTOELECTRON SPECTROSCOPY ESCA Photoelectron Spectroscopy 177 Table 1 X-Ray Molecular Orbital Spectra 178 Table 2 X-Ray Core Spectra 183 References 416 SECTION 3. ATOMIC SPECTROSCOPY Atomic Spectroscopy 421 I. Oscillator Strengths (/-Values) of Interest in Atomic Absorption Spectroscopy 421 Table 1 Oscillator Strengths (/-Values) of Interest in Atomic Absorption Spectroscopy 421

3 II. Doppler Half-Widths of Atomic Spectral Lines (Table 2) 422 III. lonization Potentials of the Elements, i.e., the Energy Required for the Process M -» M + + e' 423 Table 3 lonization Potentials of the Elements 423 IV. Dissociation Energies of Diatomic Oxide Molecules 424 Table 4 Dissociation Energies of Diatomic Oxide Molecules 424 V. Properties of Premixed Flames Used in Atomic Spectroscopy 425 Table 5 Properties of Premixed Flames Used in Atomic Spectroscopy 425 VI. Efficiences of Atomization of Metals in Flames 425 Table 6 Efficiencies of Atomization of Metals in Flames 426 References 426 VII. Measured Degrees of lonization of Metals in Flames 427 Table 7 Measured Degrees of lonization of Metals in Flames 427 Table 8 Salts Suitable for Preparing Calibration Curves 428 Table 9 Primary Wavelengths and Sensitivities for Flame Atomic Absorption Analysis 429 Table 10 Detection Limits Using Plasma MS Analysis 430 Table 11 Sensitivities (1% Absorption) and Detection Limits for Carbon Rod Atomizer (Mini-Massmann) 431 Table 12 Zeeman Background Correction Data for P.E SECTION 4. EMISSION SPECTROSCOPY Emission Spectroscopy 437 I. Comparison of Some Experimentally Determined Emission-Spectroscopic Detection Limits 437 Table 1 Comparison of Some Experimentally Determined Emission-Spectroscopic Detection Limits 437 II. Reported Relative Detection Limits for Are Excitation 438 Table 2 Reported Relative Detection Limits for Are Excitation 438 III. Relative Detection Limits for Spark Excitation of Solids 440 Table 3 Relative Detection Limits for Spark Excitation of Solids 441 IV. Detection Limits for Liquid Samples (u,g/ml) 442 Table 4 Detection Limits for Liquid Samples 442 V. Detection Limits for Micro or Residue Samples (ng) 444 Table 5 Detection Limits for Micro or Residue Samples 444 VI. Detection Limits with the Laser Microprobe ( xg/g) 446 Table 6 Detection Limits with the Laser Microprobe 446 VII. Preconcentration-Separation Procedures Used for Emission Spectrometric Analyses 447 Table 7 Preconcentration-Separation Procedures Used for Emission Spectrometric Analyses 447 References 447 VIII. Sensitive Lines for Use in Atomic Emission Spectrometry 448 Table 8 Sensitive Lines for Use in Atomic Emission Spectrometry 448 IX. Wavelengths Commonly Recommended for Use in Plasma Emission 460 Table 9 Wavelengths Commonly Recommended for Use in Plasma Emission 460 X. Prominent Lines Used in Plasma Emission 462 Table 10 Prominent Lines Used in Plasma Emission with Detection Limits and Elements Which May Cause Spectral Interference 462

4 XI. Comparison of Detection Limits for AES, AAS, and AFS 469 Table 11 Comparison of Detection Limits for Atomic-Emission (AES), Atomic-Absorption (AAS), and Atomic-Fluorescence Spectroscopy (AFS) 469 XII. Wavelength Used in Flame Emission 472 Table 12 Wavelengths of Emission Lines Used for the Detection and Determination of Some Common Elements 472 XIII. Sensitivity Results Obtained with Nitrous Oxide-Acetylene Flames 474 Table 13 Sensitivity Results Obtained with Nitrous Oxide-Acetylene Flames 474 XIV. Results Obtained with Shielded Burners 475 Table 14 Results Obtained with Shielded Burners 475 XV. Relative Sensitivities Detection Limits 476 Table 15 Relative Sensitivities Detection Limits 476 SECTION 5. INFRARED SPECTROSCOPY Infrared Spectroscopy 481 I. Sampling 481 Properties of Common Window Materials 481 Properties of Common Solvents 495 Spectra of Common Solvents 496 II. Calibration: Secondary Standards for Wavelengths 509 III. Spectrometer Operation 512 The Coblentz Society Specifications for the Evaluation of Infrared Reference Spectra: Class II Spectra 512 Class III Spectra 515 Table 1 Absorption Maxima Recommended for Calibration Purposes 515 Spectral Slit Width of a Gräting Monochromator 518 Relationship Between Noise (N), Slit Width (s), and Response Time (T) 518 Determination of Scan Speed from the Spectrometer Time Constant and the Half-Band Width 518 Theoretical Transmittance of Mylar Beamsplitter Foils 518 IV. Interpretation 519 Common Spurious Absorption Bands and Their Origin 519 Wavelength-to-Wavenumber Conversion Tables and Refractive Index of Standard Air, 2 20 (j-m 520 Numbering of Fundamental Vibrational Frequencies in Molecules 523 Infrared Correlation Charts and Tables 524 Correlation Chart of Infrared Group Frequencies 529 V. Quantitative Analysis 534 Absorption Laws 534 Determination of Stray Radiation 534 To Minimize Errors in Quantitative Analysis 534 References 535 Measurement of Absorbance 535 SECTION 6. RAMAN SPECTROSCOPY Raman Spectroscopy 539 I. Instrumentation 539 Sources 539 Table 1 Major Wavelengths for Some Common Gas Lasers 539

5 Monochromators 539 Detector and Amplification 539 II. Spectrometer Operation 539 Monochromator Parameters 539 Table 2 Possible Spurious Lines due to Emission from the Laser Plasma When an Argon Laser is Being Used as the Raman Exciting Source 540 Spectrometer Calibration 542 Resolution Check 543 Intensity Dependencies 543 Table 3 Table 4 Calibration of Laser Raman Spectrometers for Helium-Neon Excitation 546 Calibration of Raman Spectrometers for Argon Ion Laser Excitation 546 Depolarization Ratios 547 III. Sampling and Geometry 547 Conventional Solid and Liquid Phase Geometry 547 Table 5 Routine Calibration of the Laser Raman Spectrometer with Indene 549 Table 6 Chlorine Isotope Bands 549 Special Geometries 549 Table 7 Comparison of Different Laser Excitation Frequencies 550 Microsampling 550 IV. Interpretation 550 V. Representative Raman Spectra 550 Table 8 A Summary of Characteristic Raman Frequencies 551 VI. The Documentation of Raman Spectra 556 Recommendation for the Presentation of Raman Spectra for Cataloging and Documentation in Permanent Data Collections 556 Recommendations 562 References 562 SECTION 7. ULTRA VIOLET ABSORPTION SPECTROSCOPY Ultraviolet Absorption Spectroscopy 565 I. Ultraviolet: Spectral Data Index 565 SECTION 8. ELECTRON SPIN RESONANCE Electron Spin Resonance 649 I. Introduction 649 II. Physical Constants and Conversion Factors 650 Table 2-1 Conversion Factors 650 Table 2-2 Energy Conversion Factors 650 Table 2-3 Nuclear Spins, Abundances, Moments and Hyperfine Couplings for Some Common Magnetic Nuclei 651 III. Instrumentation 653 Block Diagram of Superheterodyne Spectrometer 653 Sensitivity 653 Resonance Cavities 655 Table 3-1 Electrical Properties of Several Metals, Where / Is in the Units Hz 655 Table 3-2 Dielectric Properties of Materials Sometimes Encountered Inside Cavities 660

6 IV. Theory 661 The Spin Hamiltonian 661 Crystal Fields 661 Spin Orbit Interaction 662 Zero Field Splittings 662 Table 4-1 Coefficients C 4 and D 6 for Three Coordinations 662 Table 4-2 List of Operator Equivalents to Some Commonly Occurring Functions Within a Manifold of Given J, the Summation Being Over the Coordinates of the Magnetic Electrons 664 Quadrupole Interaction 667 V. Transition Ions 668 Table 5-1 ESR Data for Transition Group Ions in Magnesium Oxide (MgO) 669 Table 5-2 ESR Data for Transition Group Ions in Spineis (AB ) 672 Table 5-3 ESR Data for Transition Group Ions in Corundum (A ) 673 VI. Free Radicals 675 Table 6-1 Hyperfine Characteristics of Typical Ions and Radicals in the Liquid Phase 676 Table 6-2 Variation in g Values for DPPH at Room Temperature 677 VII. Relaxation 677 Introduction 677 Bloch Equations 677 Modified Bloch Equations 677 Exchange 678 Motional Effects on Relaxation 678 Relaxation in Solids 678 Saturation Method of Measuring Relaxation Times 679 Table 7-1 Typical Temperature and Field Dependence Formulas for the Spin-Lattice Relaxation Time T, 681 Table 7-2 Characteristics of Relaxation Times in Solids and Liquids 681 Pulse Techniques and Spin Echos 682 VIII. Lineshapes 685 Lorentzian and Gaussian Lineshapes 685 Table 8-1 Comparison of Gaussian and Lorentzian Lineshapes 687 Zero Field Powder Pattern Lineshape 688 Dipolar Lineshapes 688 Anisotropie g-factor and Hyperfine Tensors 688 Inhomogeneous Lines 689 IX. Electron Nuclear Double Resonance 691 Acknowledgments 693 References 693 SECTION 9. MASS PHOTOELECTRIC ABSORPTION COEFFICIENTS Mass Photoelectric Absorption Coefficients 701 Introduction 701 Table of Mass Absorption Coefficients for K Alpha 1 Lines 702 Table of Mass Absorption Coefficients for K Beta 1 Lines 714 Table of Mass Absorption Coefficients for L Alpha 1 Lines 724 Table of Mass Absorption Coefficients for L Beta 1 Lines 743 Table of Mass Absorption Coefficients for M Alpha Lines 762 Table of Mass Absorption Coefficients for M Beta Lines 771

7 SECTION 10. APPEARANCE POTENTIAL SPECTROSCOPY Appearance Potential Spectroscopy 781 Introduction 781 Introduction to Table of Atomic Energy Levels 782 Table 1 Atomic Energy Levels 783 References 793 SECTION 11. THERMAL NEUTRON CROSS SECTIONS AND RESONANCE INTEGRALS FOR ACTIVATION ANALYSIS Thermal Neutron Cross Sections and Resonance Integrals for Activation Analysis 797 Introduction 797 References 797 Table 1 Thermal Neutron Cross Sections and Resonance Integrals 798 SECTION 12. X-RAY FLUORESCENCE AND COSTER-KRONIG YIELDS FOR THE K-, L-, AND M-SHELLS Tables of Experimental Values of X-Ray Fluorescence and Coster-Kronig Yields for the K-, L-, and M-Shells 829 Introduction 829 Description in Terms of the Altered Vacancy Distributions (V*) 830 Description in Terms of the Primary Vacancy Distributions (N*) 830 Transformation Equations Relating the Two Descriptions 831 Table 1 Experimental Values of Low-Z K X-Ray Fluorescence Table 2 Yields 834 Experimental Values of K-Shell X-Ray Fluorescence Yields 835 Table 3 L-Subshell Fluorescence Yields 837 Table 4 Coster-Kronig Transition Probabilities in the L-Subshells 838 Table 5 Average L-Shell Fluorescence Yields 839 Table 6 M-Shell Fluorescence and Coster-Kronig Yields 840 References 843 SECTION MeV NEUTRON ACTIVATION CROSS-SECTIONS 14 MeV Neutron Activation Cross-Sections 847 Introduction 847 Activation Cross-Section Data 848 Table 1 Activation Cross-Sections for the Formation of 14.5 MeV Neutron-Induced Major Nuclear Reaction Radioactive Products 850 References 867 SECTION 14. WAVELENGTH STANDARDS IN VISIBLE, ULTRA VIOLET, AND NEAR-INFRARED SPECTROSCOPY Wavelength Standards in Visible, Ultraviolet, and Near-Infrared Spectroscopy 871 Primary Standard 871 Secondary Standards 871 Vacuum-Ultraviolet Standards 871 Table 1 Class A Secondary Standards of Wavelength 872

8 Table 2 Class B Secondary Standards of Wavelength Lines of the Iron Are in Air 872 Table 3 Proposed Secondary Standards of Wavelength: Lines of Krypton Table 4 Vacuum Wavelengths of Mercury-198 Lines 878 Interconversion of Wavelengths Measured in Air and in Vacuum 878 Table 5 Ritz Standards of Cu II in the Vacuum Ultraviolet 879 Table 6 Standard Wavelengths of Si I in the Vacuum Ultraviolet 879 Table 7 Refractive Index of Standard Air and Vacuum Correction for Wavelengths Measured in Air 881 References 881 SECTION 15. WAVELENGTH-DEPENDENT AND ELECTRONIC SYSTEM OSCILLATOR STRENGTHS FOR FREE DIATOMIC MOLECULES OF ASTROPHYSICAL IMPORTANCE Wavelength-Dependent and Electronic System Oscillator Strengths for Free Diatomic Molecules of Astrophysical Importance 885 Introduction 885 Nomenclature and Symbols 885 Absorption and Emission Spectroscopy 886 Detailed Balance 887 Lifetime Measurements 887 Ab Initio Calculations 888 Building-Up Concepts 888 More Nomenclature 890 Factoring the Transition Moment 890 R e and f el (X.) as Functions of Wavelength 891 Approximate Relationship Between f el (X) and f^" 892 Still More Notation and f Av 892 Relations Between Band and Band-System Oscillator Strengths 893 Numerical Data 894 Acknowledgments 894 Table 1A Statistical Weight w, in Equation Table 1B Statistical Weight w 2, in Equation Table 2 Notations for Strengths and Oscillator Strengths 896 Table 3 Notations for Wavelength-Dependent Oscillator Strength as Used in This Chapter 896 References 897 Index 901