Hydrogen Molecules in Crystalline Silicon Treated with Atomic Hydrogen

We report the first observation of the vibrational Raman spectrum of hydrogen molecules H₂ in crystalline silicon treated with hydrogen atoms at 400 ^∘{}C. The Raman spectrum of H₂ in silicon observed at room temperature exhibits a frequency shift of around 4158cm^-1 and a very broad half-width of approximately 34cm^-1. An isotope shift was also detected at around 2990cm^-1 in silicon treated with deuterium atoms at 400 ^∘{}C. The frequency shifts of the observed lines are in close agreement with those reported for H₂ and D₂ in the gas, liquid, and solid phases.