An experimental and theoretical study of the electronic spectrum of HPS, a second row HNO analog

Abstract

The à (1)A" - X (1)A' electronic spectra of jet-cooled HPS and DPS have been observed for the first time, using a pulsed discharge jet source. Laser induced fluorescence spectra were obtained in the 850-650 nm region. Although the 0(0)(0) band was not observed, strong 3(0)(n) and 2(0)(1)3(0)(n) progressions and 3(1) hot bands could be assigned in the HPS LIF spectrum. Single vibronic level emission spectra were also recorded, resulting in the determination of all three HPS ground state vibrational frequencies. High level ab initio calculations were used to help confirm the vibronic assignments by calculation of transition energies, anharmonic vibrational frequencies, and anharmonic Franck-Condon factors. Ab initio potential energy surfaces gave an equilibrium structure for the X (1)A' state of r"(PH) = 1.4334 Å, r"(PS) = 1.9373 Å, θ" = 101.77° and for the à (1)A" state of r'(PH) = 1.4290 Å, r'(PS) = 2.0635 Å, and θ' = 91.74°. The rotational contours observed are consistent with these structures, confirming that the bond angle of HPS decreases on electronic excitation. Although the bond angles of HNO and HNS open in the excited state, in accord with the Walsh predictions for 12 valence electron HAB molecules, HPO, HAsO and now HPS all show the opposite behavior.

The pure rotational spectrum of HPS ($\tilde{\rm X}^1 {\rm A}^{\prime}$X̃1A′): Chemical bonding in second-row elements

“…For HPS, the likely state involved is A 1 A , which correlates with a 1 i state in the linear limit. 24 As this expression suggests, the nuclear spin-rotation parameters should be proportional to the respective rotational constants, if the second-order effect dominates. The C aa , C bb , and C cc constants for HPS have the values of 0.701 MHz, 0.0371, and 0.0091 MHz, respectively, which closely correlate with the rotational constants A 0 = 264,001 (36), B 0 = 8,379.1510 (22), and C 0 = 8,111.2313 (21).…”

“…Theà 1 A −X 1 A electronic transitions of HPS and DPS have also been measured very recently using laser-induced fluorescence and single vibronic level emission spectroscopy. 24 Here we report the first measurements of the pure rotational spectrum of HPS and its D and 34 S isotopologues from microwave to submillimeter wavelengths. Both direct absorption and Fourier transform methods were employed in this study, as well as high-level quantum-chemical calculations, which assisted in the experimental investigation.…”

Simulation of the single-vibronic-level emission spectrum of HPS

“…Very recently, Grimminger et al have reported thẽ A 1 A −X 1 A laser induced fluorescence (LIF) and singlevibronic-level (SVL) emission spectra of HPS and DPS. 1 In order to assist spectral assignments, density functional theory (DFT) calculations, and both single-reference (SR) and multi-reference (MR) ab initio calculations were carried out. 1 In addition, anharmonic Franck-Condon factors (FCFs) between the two states involved were computed with a "quick and dirty" approach (their quotes; see Ref.…”

“…1 In order to assist spectral assignments, density functional theory (DFT) calculations, and both single-reference (SR) and multi-reference (MR) ab initio calculations were carried out. 1 In addition, anharmonic Franck-Condon factors (FCFs) between the two states involved were computed with a "quick and dirty" approach (their quotes; see Ref. 1 for details), employing computed coupled-cluster single and double plus perturbative triples {CCSD(T)} and complete active space self-consistent field multi-reference configuration interaction (including Davidson corrections) (CASSCF/MRCI) potential energy functions (PEFs) for the two electronic states, respectively, using the augmented correlation consistent polarized valence quadruple-zeta {aug-cc-pV(Q+d)Z} basis set.…”

“…However, although computed FCFs of theà 1 A ←X 1 A (0, 0, 0) excitation of HPS and DPS were published in Ref. 1, a direct comparison between the computed FCFs and experimental LIF spectra of HPS and DPS could not be made, because the observed LIF spectra were not corrected for laser power. Nevertheless, Ref.…”