Quantum dynamics and spectroscopy of dihalogens in solid matrices. I. Efficient simulation of the photodynamics of the embedded cluster using the G-MCTDH method
arXiv:1812.00227 · doi:10.1063/1.5082650
Abstract
The molecular dynamics following the electronic photoexcitation of the iodine molecule embedded in solid krypton are studied quantum mechanically using the Gaussian variant of the multiconfigurational time-dependent Hartree method (G-MCTDH). The accuracy of the Gaussian wave packet approximation is validated against numerically exact MCTDH simulations for a fully anharmonic seven-dimensional model of the cluster in a crystal Kr cage. The linear absorption spectrum, time-evolving vibrational probability densities, and energy expectation value are accurately reproduced by the numerically efficient G-MCTDH approach. The reduced density matrix of the chromophore is analyzed in the coordinate, Wigner and energy representations, so as to obtain a multifaceted dynamical view of the guest-host interactions. Vibrational coherences extending over the bond distance range $ 2.7\,\mboxÅ < R_\mathrm{I-I} < 4.0\,\mboxÅ$ are found to survive for several vibrational periods, despite extensive dissipation. The present results prepare the ground for the simulation of time-resolved coherent Raman spectroscopy of the -krypton system addressed in a companion paper.