CHEMISTRY SPECTROSCOPY Spring 2007

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1 CHEMISTRY SPECTROSCOPY Spring 2007 Instructor: David Perry KNCL 302 phone: DPerry@UAkron.edu Prerequisites: - Quantum chemistry or quantum mechanics at the graduate or undegraduate level - The lectures will assume at least 4 semesters of college level mathematics. - You will need a minimal skill at computer calculations. - OR permission of instructor. Credits: 3 Philosophy: This course is designed to familiarize the student with the classic works in the field and to discuss problems and techniques at the frontier of current research. The course deals with the physical principles involved in a wide range of spectroscopies and involves some mathematical derivations. An individual project will provide the opportunity for in depth study in areas of interest to individual students and give a taste for research-level spectroscopy. Lectures: Tues. and Thurs. 12:15 1:30 PM in CAS 133 Office hours: Tues. 2:00 3:00 PM; Wed. 1:15 2:15 PM Text: Peter F. Bernath, Spectra of Atoms and Molecules. No single text is adequate for this course; the lecture material will be taken from a wide variety of sources. One of the objectives of the course is to make you familiar with the classic works on the reading list. Examinations: One mid term exam: Thurs. Apr 12 during class period. Homework: Generally 1 problem set per week; there will be fewer assignments toward the end of the semester. Students will be asked to take turns writing solutions for distribution to the class. Course Credit: Homework and participation 20% Individual Project 40% Mid term exam 40% TOTAL 100% What I cannot create, I do not understand. Richard Feynman

2 Individual Project Topic due by: Thurs. Feb. 22. Project Due date: Thurs. May This project must be done individually. - With the aid of a computer, synthesize a spectrum for one molecule in a limited spectral region. Possible Topics (i) a band in the electronic spectrum of a diatomic molecule. e. g., I 2, BaF, H 2, OH. etc. (ii) A vibrational band of a symmetric top molecule, e. g., NH 3, CH 3 F, CH 3 CCH, H 3 O +, etc., or of an asymmetric top molecule, e.g., CH 2 F 2, CH 2 O, HFCO. (iii) A microwave spectrum of a symmetric or asymmetric top molecule, e. g.,ch 3 CCH, H 2 O, C 2 H 3 Cl. (iv) a pressure-broadened infrared spectrum of a diatomic molecule, e. g., CO. (v) torsion-rotation structure of HOOH, CH3OH, etc. (vi) other ideas? Pick a system that is interesting for you! Talk to me about your ideas and interests. Choose a system and a temperature so that a spectrum doesn't have too many lines to 200 lines is about right. You can always lower the temperature to reduce the number of lines. Your simulated spectrum should include all of the lines in your band that have significant intensity at the temperature you have chosen. Please, only one individual may work on the same band of the same molecule. Computer Resources While this project could be done with a good quality pocket calculator, a simple spreadsheet or computer program will eliminate a lot of tedious work. Linear and symmetric rotor molecules: All you need to be able to do is repetitively evaluate certain algebraic formulae for a range of upper and lower state quantum numbers. You may use any computer and any software with which you are comfortable. Any programming environment (Fortran, Basic, C), or any spreadsheet (e.g. Excel, Quattro), and many data analysis packages (such as Igor) will enable the calculation of transition frequencies and approximate intensities. Asymmetric tops and torsional problems: For these, calculation of transition frequencies involves diagonalizing a Hamiltonian matrix, which is most easily done with a matrix algebra or symbolic manipulator package such as Matlab, Maple, MathCAD, or Mathematica. I can provide an example asymmetric rotor calculation on Maple. Standard programming languages can also be used with the help of canned diagonalization routines, but more programming effort is needed. If you aren t skilled with the tools of quantum mechanics (CHM 610) or are not comfortable with a greater computational requirement, don t pick an asymmetric top molecule or a torsional problem. If you have trouble deciding what computer or software to use, or if you don t have easy access to the software you need, please talk to me individually. Simulated Spectrum An accurate hand-drawn spectrum is fine. Those who are comfortable with computer graphics will probably want to produce a computer-drawn spectrum. A synthetic spectrum is

3 most easily produced with a spectral analysis package such as Igor, Kaleidagraph, Origin, etc., but can also be accomplished with Excel. The spectrum must be completely and accurately labelled - including the frequency scale and upper and lower state quantum numbers for each spectral line. Color-coding various subbranches can help to make a clear spectrum. Written Material to be Handed in with the Simulated Spectrum (i) A table of the transitions, line positions, and intensities that you have plotted. (ii) A listing of any program that you have written, with data and output. (iii) Give the equations and data which you use in the simulation. (iv) Define the experimental conditions which you are simulating, e.g., sample temperature and pressure. (v) All data and equations should be referenced. (vi) Discuss explicitly the approximations used in the calculations. You will have to make some decisions about the level of rigor that you will apply in calculating frequencies, intensities, and possibly lineshapes. You should understand the possible choices and make clear their relationship to your spectrum. (vii) Search the literature for the most recent developments relevant to your simulated spectrum. Discuss these developments and if possible compare your spectrum to one in the literature. Give explicitly the search commands that you have used. Do not hand in a long list of irrelevant references; include only those which are specifically relevant to your spectrum. It is best to do the literature search as soon as you decide on a project since it may help you to avoid problems. Credit is given for (i) correctness - work which is seriously in error will be returned ungraded. (ii) level of rigor and difficulty (iii) description of approximations (iv) effort expended (v) literature search (vi) complete documentation of your work including references for the equations and spectroscopic constants employed.

4 Chm 611 SYLLABUS A. LINEAR SPECTROSCOPY I Interaction of Radiation with Matter - Time-dependent perturbation theory - Einstein A and B coefficients - Raman scattering - Spectral lineshapes II Phenomenological Spectroscopy - Born-Oppenheimer approximation - Rotational spectra - Vibrational spectra - Electronic spectra III Symmetry and Group Theory - Molecular symmetry: point groups and permutation-inversion groups - Irreducible representations and how to use character tables - Selection rules - Permutation-inversion symmetry IV Vibrations of Polyatomic Molecules - Symmetry modes - Normal modes and the F-G matrix method - Beyond normal modes: large amplitude motion and coupled vibrations V Molecular Rotation - Rigid rotors and the inertial tensor - Symmetric tops - Asymmetric tops VI Magnetic Resonance - NMR - ESR B. NONLINEAR SPECTROSCOPY I Theory - Density matrix treatment of the 2-level system with equal reference to optical and magnetic cases. - Nonlinear polarization and susceptibility - A catalog of non linear phenomena II Specific Spectroscopies - examples as time permits

5 Reference Reading List for Chemistry Spectroscopy KEY: ** = on reserve + = available in the library Spring General books at an introductory level ** Gordon M. Barrow, Introduction to Molecular Spectroscopy, McGraw-Hill, [QC 451.B33] ** William A. Guillory, Introduction to Molecular Structure and Spectroscopy, Allyn and Bacon, [QC 451.G86] ** Walter S. Struve, Fundamentals of Molecular Spectroscopy, Wiley, (At a higher level than the above.) [QC454.6 S ] Classic works ** Gerhard Herzberg, Atomic Spectra and Atomic Structure, Dover, [QC 451.H ] ** Gerhard Herzberg, Molecular Spectra and Molecular Structure I. Spectra of Diatomic Molecules, Van Nostrand Reinhold, [QC 451.H464 V.1] ** Gerhard Herzberg, Molecular Spectra and Molecular Structure II. Infrared and Raman Spectra of polyatomic Molecules, Van Nostrand Reinhold, [QC 451.H v2.] ** Gerhard Herzberg, Molecular Spectra and Molecular Structure III. Electronic Structure and Electronic Spectra of Polyatomic Molecules, Van Nostrand Reinhold, [QC 451.H464 V.3] ** K. P. Huber and G. Herzberg, Molecular Spectra and Molecular Structure IV. Constants of Diatomic Molecules, Van Nostrand Reinhold, [QC 451.H464 V.4] ** C. H. Townes and A. L. Schawlow, Microwave Spectroscopy, Dover [QC 454.T7] ** E. Bright Wilson, J. C. Cross, and P. C. Cross, Molecular Vibrations, The Theory of Infrared and Raman Vibrational Spectra, Dover, [QC 454.V5 W ] High Resolution Spectroscopy ** J. Michael Hollas, High Resolution Spectroscopy, Butterworths, [QC454.H618 H64] ** J. M. Hollas, Modern Spectroscopy, Wiley, Walter Gordy and Robert L. Cook, Microwave Molecular Spectra, Wiley, Nonlinear spectroscopy and lasers ** M. D. Levenson and S. Kano, Introduction to Nonlinear Laser Spectroscopy, Academic, + J. I. Steinfeld, Molecules and Radiation, MIT Press, [QC454.M6 S ] + N. Bloembergen, Nonlinear Optics, Benjamin, A. Yariv, Quantum Electronics, Wiley, 1989.

6 + O. Svelto, Principles of Lasers, Plenum, L. Allen and J. H. Eberly, Optical Resonance in Two Level Atoms, Dover, A. Siegman, Lasers, Univ. Sci. Books, J. I. Steinfeld, Molecules and Radiation, MIT Press, Principles of nonlinear optical spectroscopy Shaul Mukamel, Oxford, 1995 Symmetry and group theory ** F. A. Cotton, Chemical Applications of Group Theory, Wiley, [QD461.C ] + M. Hamermesh, Group Theory and its Applications to Physical Problems, Addison- Wesley, P. R. Bunker, Molecular Symmetry and Spectroscopy, NRC Research Press, (Old edition by Wiley, about 1975.) + M. Tinkam, Group Theory and Quantum Mechanics, McGraw-Hill, Angular Momentum + R. N. Zare, Angular Momentum, Understanding Spatial Aspects in Chemistry and Physics, Wiley, Richard N. Zare, Valeria Kleiman, Hongkun, Robert Gordon, Angular Momentum: Understanding Spatial Aspects in Chemistry and Physics and Companion to Angular Momentum, Wiley, A. R. Edmonds, Angular Momentum in Quantum Mechanics, Princeton University Press, M. E. Rose, Elementary theory of Angular Momentum, Wiley, 1957.

Topic B. Spectral Analysis and the Classical Description of Absorption Susceptibility. Topic C. Basic Quantum Mechanical Models Spectroscopic Systems

Topic B. Spectral Analysis and the Classical Description of Absorption Susceptibility. Topic C. Basic Quantum Mechanical Models Spectroscopic Systems Chem 249: Syllabus Experimental Spectroscopy Winter Quarter 2018 Lecture: TuTh 1100a-1220p Room TBA Web Page: http://unicorn.ps.uci.edu/249/ Instructor: Prof. Robert M. Corn Overview Chemistry 249 is a