The course covers the basic theory and experimental practice of spectroscopy in molecules and condensed matter. A general review of electromagnetic waves is followed by time dependent perturbation theory and a density matrix treatment of two-level systems. The basic principles are applied electronic, vibrational and rotational spectroscopy. The course draws heavily on literature studies that exemplify the material.

We will learn about the interaction between electromagnetic radiation and molecules, beginning with a classical description, followed by more in depth semiclassical and quantum-mechanical descriptions of absorption, emission and scattering. These techniques are usually (though not always) considered “linear” spectroscopies. The subject will be further developed with the language of non-linear spectroscopy, so that a unified view of the effect of electromagnetic radiation on molecules and the effect of molecules on the electromagnetic field can be established. If time permits, we will briefly discuss some nonlinear techniques, such as coherent anti-stokes Raman spectroscopy (CARS), femtosecond pump-probe techniques and photon echoes. The course material will be somewhat continuous with that of CHM 460, Chemical Kinetics, which takes place during the second half of the semester.

1. Overview of radiation and spectroscopy
1. Radiation of energy from an oscillating dipole
2. Loretz model of the atom
1. Material polarization, susceptibility, absorption and refraction
2. Absorption lineshapes and Fourier transforms
3. Time-dependent quantum mechanics
1. Time-evolution operator
2. Time-dependent perturbation theory
3. Fermi’s “golden rule.”
4. Einstein A and B coefficients and Beer’s Law.
5. Strong fields and Rabi oscillations.
6. Vibrational spectroscopy: Normal modes
1. Infrared absorption
2. Raman, resonant and non-resonant
7. Electronic spectroscopy
1. Molecular orbitals and configuration diagrams
2. Jablonski diagrams
3. Franck-Condon principle
4. Fluorescence