Study on microscopic solvation process of Li atom in ammonia clusters: photoionization and photoelectron spectroscopies of M(NH3)n (M = Li, Li−)

Photoionization and photodetachment processes of M(NH3)n = (M = Li and Li−) are investigated. Ionization potentials (IPs) of Li(NH3)n (5 ⩽ n ⩽ 28) are found to decrease monotonously with increasing n and give IP(∞ as 1.47 eV, in agreement with the photoelectric threshold of liquid NH3. Photoelectron spectra of Li−(NH3)n (n ⩽ 10) exhibit a rapid decrease in the Li(2P)−Li(2S) separation and a red-shift of the Li(2S)−Li−(1S) type transition with increasing n. Based on these results as well as the theoretical results on the geometrical and electronic structures, we discuss the solvation state of the Li atom in (NH3)n relating to the solvated-electron formation.