Time-dependent Hartree wave packet dynamical techniques for computation of electronically excited state optical spectra of many-body quantum systems

Abstract

An approximate solution technique for computing spectra of many-body molecular systems is proposed. We focus for concreteness on 0 K electronic absorption and emission spectra. From a time-domain perspective, it is necessary to propagate a well-defined initial Schrödinger wave packet on a specified potential energy surface in order to extract such spectra. In order to perform this task for systems with many degrees of freedom, we investigate the utility of a time-dependent Hartree factorization, in which the wave packet for the complete system is variationally factorized into a product of wave packets of smaller dimensionality. This method is shown to be both flexible and reliable for prototypical model systems associated with the physical problem of impurity spectra in host crystals. Successful application is made to a recently measured emission spectrum of I2 embedded in an argon matrix.