5.80 | Fall 2008 | Graduate

Small-Molecule Spectroscopy and Dynamics


Course Meeting Times

Lectures: 3 sessions / week, 1 hour / session


The goal of this course is to illustrate how molecular structure is extracted from a spectrum. In order to achieve this goal it will be necessary to:

  1. Master the language of spectroscopists — a bewildering array of apparently capricious notation;
  2. Develop facility with quantum mechanical models by which observed energy levels may be exactly matched by the eigenvalues of some effective Hamiltonian matrix which, in turn, is expressed in terms of a minimal number of adjustable parameters (molecular constants);
  3. Predict the relative intensities and selection rules governing transitions between eigenstates, since spectra display only transition frequencies and not energy eigenvalues;
  4. Learn how to assign spectra. It is not sufficient to know that there is a molecular eigenstate at a particular energy; it is necessary to know its quantum name as well. Spectral assignment is a topic that is neglected in all textbooks except those by Herzberg, yet it is the most important, difficulty, and frequently performed task of a spectroscopist.
  5. Experimental techniques will not be discussed, except in the most superficial, photons-as-bullets formalism.

This will, in large part, be a course in applied, stationary state quantum mechanics. Aside from the last few lectures, the focus will be on energy levels, structure, and spectra, rather than experimental techniques and apparatus.

Formal requirements include:

  1. Occasional homework problems;
  2. Frequent end-of-lecture 5 minute quizzes;
  3. Some sort of group (2 or 3 students per group) project near the end of term;
  4. A brief oral final exam;
  5. Reading assignments (listed as below):


Bernath, P. F. Spectra of Atoms and Molecules. New York, NY: Oxford University Press, 1995. ISBN: 9780195075984.

Hougen, J. T. “NBS Monograph 115.” A version of “NBS Monograph 115” is available online through the National Institute of Standards and Technology.

Wilson, E. B., J. C. Decius, and P. C. Cross. Molecular Vibrations. New York, NY: McGraw-Hill, 1955.

The approach and specific material covered in Bernath’s “Spectra of Atoms and Molecules” will be quite different from the lectures.

Course Info

As Taught In
Fall 2008
Learning Resource Types
Problem Sets with Solutions
Lecture Notes
Lecture Videos