Theory of excimer vibrational relaxation and U.V. emission in solid neon

A quantitative explanation is provided for the observed UV emission from Ne₂^* molecules in solid neon. An expression involving only known molecular quantities and lattice parameters is given for the rate of vibrational relaxation of an excimer, initially formed in a highly excited level, by interaction with the phonons. This expression is used to show that relaxation cannot proceed to the ground vibrational level of Ne₂^* during the radiative lifetime of the excimer (at the low temperatures at which the experiments are done). The calculation brings out that the vibrational population is concentrated at the n = 3 level when radiation takes place. The lineshape for dissociative UV emission from the n = 3 state of the excimer is computed, and found in very good agreement with experiment.