Infrared emission spectrum and potentials of 0(u)(+) and 0(g)(+) states of Xe-2 excimers produced by electron impact

We present an investigation of the Xe2 excimer emission spectrum observed in the near-infrared range about 7800 cm−1 in pure Xe gas and in an Ar (90%)–Xe (10%) mixture for P = 0.1 MPa at T = 300 K obtained by exciting the gas with energetic electrons. The Franck–Condon simulation of the spectrum shape suggests that the emission stems from a bound–free molecular transition never studied before. The states involved are assigned as the bound (3)0+ u state related to the 6p[1/2]0 atomic limit and the dissociative (1)0+ g state with the 6s[3/2]1 limit. Acomparison with the spectrum simulated by using theoretical potentials for internuclear distances over which the vibrational eigenfunctions of the bound state have non-negligible amplitude shows that the dissociative potential does not reproduce correctly the spectrum features. A best fit, purely repulsive potential is thus proposed to accurately reproduce the observed spectrum.