He I and He II photoelectron spectra of alkali fluorides in the vapour phase

Abstract

The He I and He II photoelectron spectra of the fluorides of sodium, potassium, rubidium and caesium have been recorded in the vapour phase using a pseudo-molecular-beam technique. The observed spectra are believed to be due mainly to monomers although evidence for the dimer has been found in the spectrum of NaF and possibly CsF. The principal features in the u.v. spectra are associated with the F^– 2p^–1 ionization and the M⁺p^–1 ionization. This structure can be interpreted largely in terms of a simple ionic model. A final ionic state configuration interaction (CI) process is proposed to interpret fine structure associated with the M⁺p^–1 ionization.