DEEP UV EMISSIONS OF IONIC CS2- STATES IN NE AND AR MATRICES(F)

Pulsed electron beam excitation of 0.45 to 0.7% CsF doped in rare gas matrices at 5 K leads to emission bands at 196.5 nm (FWHM 9.6 nm) and 227 nm (FWHM 15 nm) in Ne and at 211.2 nm in Ar. The short-wavelength bands are assigned to B-2 Sigma --> X(2) Sigma transitions in the ioni c Cs2+F- excimer on the basis of transition energies, lineshapes, and the efficiency of Cs2+F- ionization by energy transfer From the host. The long-wavelength band in Ne corresponds to a C-2 Pi-A(2) Pi transit ion. The 196.5 nm band provides a large cross section for stimulated e mission of 2.5 x 10(-16) cm(2). The red shifts of 0.4 and 0.8 eV of th e B --> X emission in Ne and Ar, respectively, are discussed in terms of solvation of the Cs2+F- ion and of its dipole moment. Optimal conce ntrations are similar to those obtained for the gas phase.