Computational study of molecular hydrogen in zeolite Na–A. II. Density of rotational states and inelastic neutron scattering spectra

Part I of this series [J. Chem. Phys. 111, 7599 (1999)] describes a simulation of H2 adsorbed within zeolite Na–A in which a block Lanczos procedure is used to generate the first several (9) rotational eigenstates of H2, modeled as a rigid rotor, and equilibrated at a given temperature via Monte Carlo sampling. Here, we show that rotational states are strongly perturbed by the electrostatic fields in the solid. Wave functions and densities of rotational energy states are presented. Simulated neutron spectra are compared with inelastic neutron scattering data. Comparisons are made with IR spectra in which rotational levels may appear due to rovibrational coupling.