Accurateab initiospin–orbit predissociation lifetimes of the A states of SH and SH⁺

Abstract

Accurate ab initio calculations are performed at the aug-cc-pV6Z/MRCI level of theory on the potential energy curves of SH (A2Σ+, 4Σ−, 2Σ−, 4Π) and SH+ (A3Π, 5Σ−), and on their respective mutual spin–orbit coupling integrals. These data are incorporated into Fermi golden rule computations allowing deducing the predissociation lifetimes for SH A2Σ+ and SH+ A3Π rovibrational levels and their corresponding deuterated species. An excellent agreement is found between the experimentally known values and ours, allowing reliable lifetime predictions for the upper A state rovibrational levels not measured yet.

Fundamental aspects of recoupled pair bonds. I. Recoupled pair bonds in carbon and sulfur monofluoride

“…But, it can only form bonds with these orbitals-recoupled pair bonds-with very electronegative ligands: the SH( 4 Σ − ) state is not bound, 42,43 whereas the SF(a 4 Σ − ) state is bound by approximately 36 kcal/mol. Although the sulfur 3p lobe orbitals are concentrated on either side of the atom, they are not as spatially well separated as the carbon 2s lobe orbitals, as indicated by the high overlap of the 3p lobe orbitals, 0.86.…”

“…In fact, this is not generally the case, as demonstrated by the fact that the SH(a 4 Σ − ) state arising from S( 3 P) + H( 2 S) is not bound. 42,43 However, the SF(a 4 Σ − ) state is bound. 7,44 In other words, a recoupled pair bond involving the 3p lone pair of sulfur is conditional; it will not be formed unless the ligand has the right attributes (see below).…”

Photodissociation and photoionisation of atoms and molecules of astrophysical interest

“…Their calculation from the v = 0 and J = 0 ground-state level was adopted here and added to this additional absorption into the longer-wavelength bound-levels of the A 3 Π state, which is known to predissociate for v ≥ 1 (Gustafsson et al 1988;Brites et al 2008). Oscillator strength of transitions into the vibrational levels of A 3 Π were calculated here using the potential-energy curves and transition dipole moments of McMillan et al (2016) and the methods of Sect.…”

Theoretical spectroscopy and metastability of BeS and its cation

“…This is not surprising: For the upper states, they present more or less a diffuse nature (valence -Rydberg character) that is accounted for sufficiently enough with our large basis set and not previously. For the SH molecule, we showed recently that the inclusion of these diffuse basis functions is mandatory for the accurate computation of these spin-orbit couplings [25]. We refer to Ref.…”

“…We refer to Ref. [25] for a wide discussion. Finally, we calculate the spin-orbit constant at equilibrium (A SO,e ) for the 3 P electronic states of BeS.…”