Theoretical study of the spectroscopy and the metastability of the NS⁺cation

Abstract

The potential energy curves of the NS+ electronic states are computed at the aug-cc-pV5Z/CASSCF/MRCI level of theory. Using these highly correlated wavefunctions, we evaluated their mutual spin–orbit coupling terms and the transition moment evolutions. Then, we deduced an accurate set of spectroscopic constants and investigated the spin–orbit induced predissociation of the lowest electronic excited states of this cation. In particular, we identify a new well-bound quintet state, namely the NS+ (15Π). The NS+(15Π) v′+ ⩽ 5 levels decay radiatively to populate the NS+(1 5Σ+) state after emission of visible light, whereas the upper rovibrational levels undergo rapid spin–orbit induced predissociation processes forming S+(4S) and N(4S) fragments via the repulsive 17Σ+ state. The potential energy curve of NS (X2Π) is also computed and used together with those of NS+ electronic states for the prediction of the single ionization spectrum of NS.

Bimolecular reactions of S2+ with Ar, H2 and N2: reactivity and dynamics

“…An isotropic scattering pattern is observed, clearly showing the involvement of a collision complex, [SN 2 ] 2+ , typical for a dicationic bond-forming reaction. The observed experimental exoergicity distribution is in good agreement with the population of known electronic states of SN + , 151 and the involvement of the S 2+ states that we know dominate our S 2+ beam.…”

“…The SN + molecular ion is relevant to a range of astrophysical environments, including in comets and nebulae. [147][148][149][150][151] SN + is also important terrestrially, in man-made plasmas. 152 Fig.…”

“…Due to its astrophysical relevance, the SN + species has been the subject of experimental study, 150,153,154 and several theoretical investigations have probed the electronic states of SN + . 151,[155][156][157] In this work we use the electronic state structure calculated by Ben Yaghlane & Hochlaf (2009), 151 as it provides the most comprehensive data. The SN + ground state (X 1 S + ) lies B6.3 eV below the lowest energy dissociation asymptote of S + ( 4 S) + N( 4 S), and B8.3 eV below the second lowest energy dissociation asymptote of S + ( 2 D) + N( 4 S).…”

Discovery of the Ubiquitous Cation NS+ in Space Confirmed by Laboratory Spectroscopy

“…Several ab initio calculations have been performed for NS + (Dyke et al 1977; Karna & Grein 1986; Peterson & Woods 1988; Yaghlane et al 2005; Yaghlane & Hochlaf 2009). All of them predict a 1 Σ + ground electronic state.…”

“…From the photoelectron spectrum of NS, r e (NS + ) was estimated to be 1.440±0.005 Å (Dyke et al 1977). The calculated values for α e , the vibrational contribution to the rotational constant, range (in MHz) between 120 (Yaghlane & Hochlaf 2009) and 180 (Peterson & Woods 1988). These estimations provide an equilibrium rotational constant 24.9-25.2 GHz and B 0 between 24.84 and 25.11 GHz.…”