ELECTRON-SPIN-RESONANCE STUDIES OF P2H6+ AND PH3+ RADICAL CATIONS IN RARE-GAS MATRICES AT 4-K - COMPARISON WITH THEORETICAL CALCULATIONS

Detailed experimental and theoretical electron spin resonance (ESR) studies of the cation radicals, PH3+ and P2H6+, 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 A(iso) and A(dipolar) values calculated at the ab initio configuration interaction (CI) level. These ESR results for PH3+ clearly indicate its nonplanarity; for P2H6+, 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 PH3+ are g(parallel-to) = 2.002(1), g(prependicular-to) = 2.007(1), A(prependicular-to) = 920(3), and A(parallel-to) = 1638(15) MHz for P-31 and A (H) less-than-or-equal-to 6 MHz. The neon parameters for P2H6+ are g(parallel-to) = 2.001(1), g(prependicular-to) = 2.003(1), A(prependicular-to) = 1527(2), and A(parallel-to) = 1909(4) MHz for P-31 and A(2H) = 182(2) and A(4H) = +/- 22(2) MHz.