A Systematic Study of the X̃ 2B1, Ã 2A1, and B̃ 2B2 States of the Neutral Radical PH2

A global CHIPR potential energy surface of PH2(X2B1) via extrapolation to the complete basis set limit and the dynamics of P(2D) + H2(X1Σ+g) → PH(X3Σ−) + H(2S)

A global PEC of the ground state PH2 was constructed using the CHIPR method based on accurate MRCI(Q)/CBS(T, Q) energy points. The ICS and k(T) of P(2D) + H2(X1Σ+g) → PH(X3Σ−) + H(2S) were calculated based on the QCT method.

THE IONIZATION ENERGIES AND SIMULATED PHOTOELECTRON SPECTRA OF HPCN AND HNCP

The structures, vibrational frequencies and adiabatic ionization energies of HPCN and HNCP are calculated at several levels of theory. The adiabatic ionization energy of HPCN is found to be 10.16 eV at the G3 level of theory. The singlet state of HPCN+[Formula: see text] is found to be approximately 1.3 eV below the lowest energy triplet state (ã3A ″). Both states have a bent equilibrium molecular geometry. The adiabatic ionization energy for HNCP is calculated to be 8.30 eV at the G3 level of theory. In contrast to HPCN+, the triplet state [Formula: see text] of HNCP+is lower in energy than that of the singlet state (ã1A ′) by approximately 1 eV. Also, the triplet state of HNCP+is linear in contrast to that of HPCN+due to the larger interaction between neighboring 2p orbitals on the central atoms in HNCP+relative to the interaction between the 3p and 2p orbitals on the central atoms in HPCN+. Simulated photoelectron spectra (PES) are presented for the transitions producing both the singlet and triplet ion states of both isomers. As predicted by the dramatic geometry change in the case of [Formula: see text], there is a long progression in the bending mode of the cation in the simulated PES.

A dispersed fluorescence andab initioinvestigation of the X̃B12 and ÃA12 electronic states of the PH2 molecule

In this work, the X2B1 and A2A1 electronic states of the phosphino (PH2) free radical have been studied by dispersed fluorescence and ab initio methods. PH2 molecules were produced in a molecular free-jet apparatus by laser vaporizing a silicon rod in the presence of phosphine (PH3) gas diluted in helium. The laser-induced fluorescence, from the excited A2A1 electronic state down to the ground electronic state, was dispersed and analyzed. Ten (upsilon1upsilon2upsilon3) vibrationally excited levels of the ground electronic state, with upsilon1 < or = 2, upsilon2 < or = 6, and upsilon3 = 0, have been observed. Ab initio potential-energy surfaces for the X2B1 and A2A1 electronic states have been calculated at 210 points. These two states correlate with a 2Pi(u) state at linearity and they interact by the Renner-Teller coupling and spin-orbit coupling. Using the ab initio potential-energy surfaces with our RENNER computer program system, the vibronic structure and relative intensities of the A2A1 --> X2B1 emission band system have been calculated in order to corroborate the experimental assignments.