6533b7d0fe1ef96bd125a299

RESEARCH PRODUCT

Solvation of triplet Rydberg states of molecular hydrogen in superfluid helium

subject

description

We report ab initio interaction potentials, transition dipole moments, and radiative lifetimes for the four lowest triplet states of ${\mathrm{H}}_{2}:$ $b$ ${}^{3}{\ensuremath{\Sigma}}_{u}^{+},$ $c$ ${}^{3}{\ensuremath{\Pi}}_{u},$ $a$ ${}^{3}{\ensuremath{\Sigma}}_{g}^{+},$ and $e$ ${}^{3}{\ensuremath{\Sigma}}_{u}^{+},$ and their response to the perturbation due to approaching ground state He atom. Hybrid density functional\char21{}quantum Monte Carlo calculations employing the ab initio interaction potentials are then used for calculating the liquid structure around the molecular excimers in bulk superfluid ${}^{4}\mathrm{He}.$ Calculations demonstrate a wide variety of possible solvation structures, both spherical and highly anisotropic in geometry, depending on the electronic state of ${\mathrm{H}}_{2}.$ The experimentally observed ${\mathrm{H}}_{2}$ ${(}^{3}{e}^{3}a)$ emission bands [Trottier et al., Phys. Rev. A 61, 052504 (2000)] are simulated and the origins of the line shifts discussed. Absorption spectra of the same system are predicted to be broader and more blue shifted compared to the gas phase. Feasibility of the metastable ${}^{3}$$c$ state for absorption experiments in liquid helium is proposed.