Neon matrix ESR and CI theoretical investigation of 1BF+ and 11BF+: Photoionization of BF from reactive laser sputtering and high temperature sources

Abstract

The 11BF+ and 10BF+ radical cations have been generated and trapped in neon matrices at 4 K using the combined techniques of pulsed reactive laser sputtering and photoionization at 16.8 eV. An independent high temperature source of BF(g) in conjunction with photoionization was also employed and a comparison between these two different generation methods reveals no significant differences in their ESR spectra. The magnetic parameters for 11BF+ measured in neon matrices are g∥=2.0012(3), g⊥=2.0004(3), (11B) A∥=1784(1), and A⊥=1727(1) MHz, (19F)A∥=410(1), and A⊥=152(1) MHz. Extensive ab initio theoretical calculations have been conducted for BF+ and the nuclear hyperfine properties obtained from various types of CI wave functions show excellent agreement with the experimental measurements. Valence orbital occupancies obtained from a Mulliken-type population analysis performed on the CI wave functions are compared with the conventional free atom comparison method for obtaining electronic structure information from ESR A tensor measurements. The distribution of the unpaired electron in BF+ is compared to six other isoelectronic first row radicals.