ISSN 1017-2548(Print)
ISSN 2234-8530(Online)
Volume 52, Number 1
JKCSEZ 52(1)
February 20, 2008 

Molecular motion influencing the absorption spectrum of a chromophore in liquid is theoretically described by a quantum mechanical time correlation function. In the present paper, we developed a theoretical method to calculate such a quantum mechanical time-correlation function from a classical time-correlation function using semiclassical approximations. The calculated time-correlation function was combined with the second order cumulant expansion method to calculate the absorption spectrum of nile blue in acetonitrile. Reasonably good agreement with experimental spectrum was obtained. From the comparison with experimental spectrum, we concluded that the time scale of solvation dynamics of the system should be longer then 1ps and the first shell of solvent is the major contribution to the solvation dynamics.