Electronic and spin-rovibrational spectroscopy of the HPS plus cation

Using post Hartree-Fock multi-configuration interaction ab initio approaches, the six (four) doublet (quartet) lowest electronic states of thioxophosphane cation, HPS+, are treated. These electronic states are mapped along the internal coordinates, including the HP, PS distances and in-plane HPS bending angle. Several po-tential minima are located where long-lived HPS+ ions can be found. Also, computations show that the (X 2A', 12A, 22A, 22A', 14A'and 14A) states are bound, for which we generate their 3D-potential energy surfaces (3D-PESs). After nuclear motion treatments, we determine the rotational and vibrational constants of these states and the pattern of their rovibrational levels up to 4000 cm � 1 above the corresponding vibrational ground state level. For instance, the RCCSD(T)/aug-cc-pV(5 + d)Z anharmonic frequencies of HPS+(X 2A') are computed v1 = 2237.7, v2 = 543.0, v3 = 686.8 (in cm � 1). For the lowest electronic excited state (HPS+(12A)), these frequencies change to v1 = 2330.5, v2 = 254.6 and v3 = 749.6 (in cm � 1). Several anharmonic resonances are identified. Besides, a very accurate adiabatic ionization energy of HPS (= 9.3173 eV) is deduced using the (U)CCSDT(Q)/aug-cc-pV(T + d)Z approach and where the core-valence (& UDelta;CV), scalar relativistic (& UDelta;SR) and zero point vibrational energy (& UDelta;ZPE) corrections are included. Our spectroscopic data should be useful for identifying this ion in laboratory and in media where reactive collisions between PS/PS+ + H+/H or HP/HP+ + S+/S are taking place.

Automated summary

Using post Hartree-Fock multi-configuration interaction ab initio methods, the electronic states and potential energy surfaces of thioxophosphane cation, HPS+, are studied. The rotational and vibrational constants and rovibrational levels of these states are determined. An accurate adiabatic ionization energy of HPS is also deduced. This research provides useful spectroscopic data for identifying HPS+ in laboratory and in reactive collision media.