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A new interpretation of the meaning of the center of line slope from a two-dimensional infrared spectrum.

Authors :
Falvo, Cyril
Source :
Journal of Chemical Physics. 2016, Vol. 144 Issue 23, p1-9. 9p. 1 Diagram, 2 Charts, 6 Graphs.
Publication Year :
2016

Abstract

This article presents a new approximation to understand the connection between the center of line slope from a single peak of a two-dimensional (2D) infrared spectrum and the frequency-frequency correlation function. This approximation which goes beyond the short-time approximation includes explicitly pure dephasing mechanisms by introducing a time parameter that separates the fast fluctuations and slow fluctuations. While in the short-time approximation, the center of line slope is given by the normalized frequency fluctuations auto-correlation function, I show using this new approximation that the center of line slope measures on long time scales a shifted and scaled correlation function. The results present a new interpretation of the meaning of the center of line slope that allows for a better understanding of what 2D experiments can measure. To illustrate these findings, I compare this approximation with the short-time approximation for several examples of frequency-frequency correlation functions. I also give an estimate of the value of the time separation parameter for a correlation function with a simple exponential decay. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
00219606
Volume :
144
Issue :
23
Database :
Academic Search Index
Journal :
Journal of Chemical Physics
Publication Type :
Academic Journal
Accession number :
116392412
Full Text :
https://doi.org/10.1063/1.4953848