Probing quantum solvation with infrared spectroscopy: infrared activity induced in solid parahydrogen by N2 and Ar dopants

We present the first high-resolution study of the infrared (IR) absorption spectra of solid parahydrogen matrices containing low concentrations of N2 or Ar impurities. The spectra reveal dopant-induced absorption features that acquire IR activity through short-range isotropic vibrational transition dipole moments arising from dopant–H2 intermolecular interactions. These dopant-induced features provide new insights into the perturbation of the vibron bands of the H2 matrix by chemical impurities, and thus into the physics of solvation in a quantum solid.