Mass spectrometric determination of appearance energies for ions formed from CoF(4) and CoF(3) molecules

Knudsen cell mass spectrometry was applied to the evaluation of the ionization efficiency curves for the ions originating from CoF(4) molecules. Cobalt tetrafluoride was obtained in the gas phase over the CoF(3)(s)-TbF(4)(s) system in the temperature range from 640 to 690 K. From the ionization efficiency curves the appearance energies of the ions formed from the CoF(4) molecules were determined by means of Vogt's deconvolution method. Clausius-Clapeyron plots for the ions from CoF(4) molecules were measured. Evaporation of pure CoF(3)(s) was carried out, and the appearance energies of the ions formed from CoF(3) molecules were determined. The ionization energies for CoF(4) and CoF(3) molecules were found to be (14.3 +/- 0.2) and (13.3 +/- 0.1) eV, respectively.