Calculation of the libron spectrum in solid H2 and D2

The k = 0 libron energies in solid hydrogen are calculated including the interactions between widely separated molecules. Comparing these results with the observed Raman spectrum gives the interaction coefficients, Гeff = 0.48 cm-1 for H2 and Гeff = 0.67 cm-1 for D2. These values are respectively 20 and 15 per cent lower than those obtained neglecting these interactions.