Electron spin resonance studies of P2H+6 and PH+3 radical cations in rare gas matrices at 4 K. Comparison with theoretical calculations

Abstract

Detailed experimental and theoretical electron spin resonance (ESR) studies of the cation radicals, PH+3 and P2H+6, isolated in neon and argon matrices are reported. These cations were generated by photoionization (17 eV) and x-irradiation (80 keV) methods. The observed nuclear hyperfine interactions (A tensors) showed reasonable agreement with Aiso and Adipolar values calculated at the ab initio configuration interaction (CI) level. These ESR results for PH+3 clearly indicate its nonplanarity; for P2H+6, an earlier theoretical prediction of a C2h distortion from C3v was confirmed by these new experimental results which reveal two different H atom environments. The neon magnetic parameters for PH+3 are g∥=2.002(1), g⊥=2.007(1), A⊥=920(3), and A∥=1638(15) MHz for 31P and A(H)≤6 MHz. The neon parameters for P2H+6 are g∥=2.001(1), g⊥=2.003(1), A⊥=1527(2), and A∥=1909(4) MHz for 31P and A(2H)=182(2) and A(4H)=±22(2) MHz.