Solvation of triplet Rydberg states of molecular hydrogen in superfluid helium

We report ab initio interaction potentials, transition dipole moments, and radiative lifetimes for the four lowest triplet states of H2: b 3Σu+, c 3Πu, a 3Σg+, and e 3Σu+, and their response to the perturbation due to approaching ground state He atom. Hybrid density functional-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 4He. Calculations demonstrate a wide variety of possible solvation structures, both spherical and highly anisotropic in geometry, depending on the electronic state of H2. The experimentally observed H2 (3e→3a) 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 3c state for absorption experiments in liquid helium is proposed