15min:

R. J. HINDE, Department of Chemistry, University of Tennessee, Knoxville, TN 37996.

The infrared absorption spectrum of atom- and molecule-doped solid parahydrogen (p-H₂) exhibits features near 4160 cm^-1 which are absent from the spectrum of pure solid p-H₂. These absorption features are associated with the Q₁(0) pure vibrational transitions of H₂ molecules located near impurities; the transition moment responsible for this infrared activity arises from weak overlap-induced dopant--H₂ and H₂--H₂ dipoles, and from dopant-induced symmetry breaking of the p-H₂ crystal lattice. Because the transition dipole moment for these infrared features depends sensitively on the structure of the p-H₂ matrix surrounding the dopant, studies of the Q₁(0) absorption feature could provide detailed information about the physics of solvation in highly quantum systems. We present the results of diffusion quantum Monte Carlo (DQMC) simulations of the Q₁(0) absorption lineshape for isolated dopants in solid p-H₂, and briefly discuss the structural and dynamical information provided by our DQMC simulations.