Nonradiative relaxation of excited vibrational states of solid hydrogen.

The vibrational-rotational relaxation of the molecular hydrogen in solid phase is measured utilizing the transient optothermal lensing effect. We have obtained the relaxation rates for the first, second and third vibrational levels leading to k(v) ~~ vx1.89x10(5)sec(-1), where v is the vibrational quantum number. This relationship is consistent with the energy gap law and is a manifestation of the multiphonon relaxation mechanism.