An ab initio study of multiphoton bound-bound electronic transitions of H₂S

Abstract

Multiphoton absorption properties of H2S, transition probability coefficients and polarisation ratios are studied at ab initio level according to quantum electrodynamical methods, by employing RPA vertical excitation energies and transition moments and taking the random molecular orientation into account. The spectral observables associated with absorption of two, three and four photons with identical frequency and polarisation for the low-lying singlet excited states are reported. The concerted absorption of two or three photons with various polarisations from two laser beams is investigated as a function of the photon energies. The magnitude and direction of the electrochromic effects induced by a static external electric field on the molecular two-photon spectral properties are also analysed.

The Study of the Low-Lying Valence-Shell Excitations of Hydrogen Sulfide by Fast Electron Impact

“…The OOS of this state measured by the photoabsorption method is obviously lower than the current result and the one of the dipole­(e,e) experiment . As for the theoretical calculations, the excitation energies calculated by Galasso and Velasco et al are in good agreement with the experimental results, while the calculated OOSs of the 4sa 1 state ,, are higher than the experimental ones as shown in Table and Figure . The OOSs of other electronic states have also been calculated theoretically in refs , , and , while the reported OOSs for each of these states include the contributions of all their vibronic bands.…”

“…As for the theoretical calculations, the excitation energies calculated by Galasso and Velasco et al are in good agreement with the experimental results, while the calculated OOSs of the 4sa 1 state ,, are higher than the experimental ones as shown in Table and Figure . The OOSs of other electronic states have also been calculated theoretically in refs , , and , while the reported OOSs for each of these states include the contributions of all their vibronic bands. However, the present work obtains some vibronic OOSs of these electronic states rather than the electronic ones due to the overlapping between these bands, so the present data cannot be compared with the theoretical electronic ones directly.…”

“…Theoretically, the excitation energies and the OOSs of the valence-shell excitations of H 2 S have been calculated by various methods, such as the ab initio self-consistent field (SCF), the configuration interaction (CI), , the random phase approximation (RPA), single-excitation configuration mixing, and the multireference single and double configuration interaction (MRSDCI) methods. On the other hand, the dissociation mechanism of the feature in the 185–210 nm region has also been calculated by the multiconfigurational self-consistent field (MCSCF) and multiple reference double-excitation configuration interaction (MRDCI) methods. , In these works, the existence of the two electronic states of the 3b 2 1 A 2 and 4sa 1 1 B 1 in this region was proposed to explain the characteristics of this feature, while the former is dipole-forbidden and inaccessible in the photoabsorption experiments.…”

Theoretical study of molecular properties of low-lying electronic excited states of H2O and H2S

“…In Table 2 we presented just most recent ones [3,[15][16][17][18]. All of these [6,7,[22][23][24][25][26][27][28][29][30]. We present few most recent relevant data [23,[26][27][28] in Table 2.…”

Photodissociation of hydrogen sulfide at 157.6 nm: Observation of SH bimodal rotational distribution

“…Experimentalists have obtained an increasing wealth of data, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] while theoretical investigations have aimed at better and more complete potential energy surfaces ͑PES͒ and a better understanding of the dynamics. [16][17][18][19][20][21][22][23] Spectroscopy of the H 2 S molecule has also been studied quite extensively using absorption [24][25][26][27] and resonance-enhanced multiphoton ionization ͑REMPI͒ techniques. [28][29][30][31] The first UV absorption band of hydrogen sulfide peaks at ϳ195 nm.…”