The Submillimeter‐Wave Spectrum of the CS⁺Radical Ion

Abstract

The submillimeter-wave spectrum of the CS + radical cation in its ground electronic state (X 2 AE + ) has been observed for the first time, in a flowing positive column discharge in a CS 2 -Ar mixture partially cooled with a limited flow of liquid nitrogen. Nine rotational transition frequencies were recorded between 414 and 622 GHz, leading to the determination of accurate molecular constants B 0 = 25908.8560(41) MHz, D 0 = 41.344(18) kHz, and 0 = 597.629(41) MHz, which we use to predict transition frequencies up to the terahertz region in order to stimulate new attempts at astronomical detection.

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

“…All their cations, except NS + and PO + , have spin multiplicity >1 in their ground electronic state. For example, CS + , has a 2 Σ + electronic state, B = 25.9 GHz and D = 41.3 kHz (Bailleux et al 2008), while CP + has a 3 Π ground electronic state with B e ∼ 21.5 GHz (Bruna & Peyerimhoff 1980). PO + has a singlet electronic state with B = 23.512 GHz (Petrmichl et al 1991).…”

Accuracy of Rotational Parameters Predicted by High-Level Quantum-Chemical Calculations: Case Study of Sulfur-Containing Molecules of Astrochemical Interest

“…The rotational constants considered in the statistical analysis range from 2.7 to 310 GHz, therefore only a discussion in terms of relative errors is meaningful . A summary of the experimental constants considered − can be found in the Supporting Information (SI).…”

“…The latter is an important point because core correlation for second-row elements often needs cc‑pCV5Z basis sets to be correctly taken into account. Indeed, there is some indication in the literature that the use of a quadruple-ζ basis set is not sufficient. , As before the discussion is in terms of relative errors and the experimental values used as reference − ,− are reported in the SI.…”

“…Indeed, there is some indication in the literature that the use of a quadruple-zeta basis set is not sufficient. 57,81 As before the discussion is in term of relative errors and the experimental values used as reference [48][49][50][51][52][53][54][55][56][57][58][59][60][61][62][63][82][83][84][85][86][87][88][89][90][91][92][93] are reported in the SI. Table VII: Statistical analysis of the relative errors (in %) in the computed rotational constants with respect to B i e values derived from experimental B i 0 values corrected for vibrational contribution computed at the CCSD(T)/cc-pCVQZ level.…”

Absorption spectrum of the (2,1) band in the A2Пi–X2Σ+ system of CS+ cation

“…The carbon sulfide cation (CS + ) is an important molecular ion of sulfur compound in astronomy [1][2][3][4] and its spectra have continuously attracted attention both from astrophysicists and spectroscopists. In 1976, Coxon et al [5] first recorded the spectrum of the A 2 G i -X 2 R + system of CS + through the reaction of metastable He (2 3 S) with CS 2 .…”