Emission Spectra of Group 13 Metal Atoms and Indium Hydrides in Solid H₂ and D₂

Infrared spectra of solid hydrogen (deuterium) samples co-deposited at 3.5 K with laser-ablated Al, Ga, In, and Tl atoms reveal infrared absorptions for the MH [MD] molecules. Irradiation at 193 nm increases MH 2 and MH 3 [MD 2 and MD 3 ] absorptions and produces emission spectra for the metal atoms except for Al and phosphorescence spectra for the InH [InD] molecules. Unreacted metal emission bands are blue-shifted from the gas phase more by solid D 2 than by solid H 2 . However, the emission yield for InD is much higher in solid D 2 than for InH in solid H 2, which suggests a higher nonradiative relaxation rate in solid H 2 than in solid D 2 owing to the larger zero-point motion.