The 1st Symposium on
Multidimensional Vibrational Spectroscopy in 2002
Title/Abstract Form
Name: Mark Berg
Organization: University of South Carolina
Address: Department of Chemistry and Biochemistry
Home Page: http://www.chem.sc.edu/faculty/berg/
Title: Quadratic Coupling and Non-Gaussian Dynamics in Nonlinear Spectroscopy
Authors: Mark Berg
Abstract:
Gaussian dynamics and linear coupling are widely assumed in the analysis of nonlinear
spectroscopies. Under these assumptions, the information content of the experiments
reduces to a single one-dimensional function – the frequency autocorrelation function
M(t). We present several experimental examples where these approximations violated
in a substantial way.
These include torsional motion in a conjugated polymer,
poly(phenyleneethynylene), vibrational dephasing in alkylbenzenes, and solvation
dynamics in DNA. In each case, the frequency distributions are strongly non-Gaussian
and change width or shape during the relaxation. In these cases, the additional
dimensions available in nonlinear spectroscopy take on added importance in
interpreting the relaxation dynamics.