Calculation of Electronic-Excited-State Absorption Spectra of Water Clusters Using Time-Dependent Density Functional Theory

摘要

Calculations are presented of electronic-excited-state absorption spectra for molecular clusters of H_2O using time-dependent density functional theory (TD-DFT). Calculation of excited state resonance structure using TD-DFT can provide interpretation of absorption spectra with respect to molecular structure for excitation by electromagnetic waves at frequencies within the UV-visible range. The absorption spectrum corresponding to electronic excitation states of a molecular cluster consisting of a relatively small number of water molecules should be associated with response features that are intermediate between that of isolated molecules and that of a bulk lattice. TD-DFT calculated absorption spectra represent quantitative estimates that can be correlated with additional information obtained from laboratory measurements and other types of theory based calculations. The DFT software GAUSSIAN was used for the calculations of electronic excitation states presented here.