Chapter 3 Parallel Computing of Resonance Raman Intensities Using a Transputer Array

Abstract

The computational approaches have a great importance in solving the problems of spectral processing, interpretation, and simulation—for example, computing the resonance Raman (RR) intensities of large molecules provides detailed information about the equilibrium geometry and dynamics of the resonant excited electronic state. The traditional approach to calculating the RR cross section involves a summation over all the vibrational levels of the resonant electronic state. Such a sum-over-state algorithm performs a direct search for the complete set of excited state parameters that generate the best fit to the experimental RR data. Usually, when there are only a few RR active modes, the sum-over-state method is much more efficient compared with alternative approaches. The chapter further explains computing resonance Raman and absorption cross sections. The resonance Raman cross section in the Condon approximation can be written as the conventional vibronic sum-over-states. The hardware and software environment is also explained in the chapter.