ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
We analyze two strategies for calculating the signal in a time-resolved, coherent light scattering experiment in which intermolecular motions, such as phonons in a molecular crystal, are excited. In the first strategy, the detected radiation is quantized, and the signal intensity is calculated to eighth order in perturbation theory. In the second method, this radiation is treated classically, and the signal amplitude is calculated to fourth order in perturbation theory. Each of these approaches has been used in the literature of nonlinear spectroscopy. We establish that for a general model of molecules whose electronic transitions are coupled to intermolecular motions, the two approaches are not formally equivalent. We present calculations of the experimental observable for a model of a molecular crystal with linear exciton–phonon coupling. These calculations allow us to determine the relative importance of contributions to the signal from phonon dynamics of the crystal in its electronic ground state and from dynamics of the electronically excited crystal. A similar analysis is performed for coherent light scattering from intramolecular vibrations.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.459388
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