MARVEL analysis of high-resolution spectra of thioformaldehyde (H2CS)

Rotational spectroscopy of the thioformaldehyde isotopologues H 2 CS and H 2 C 34 S in four interacting excited vibrational states and an account on the rotational spectrum of thioketene, H 2 CCS

“…We have inspected calculated transition frequencies of H 2 CS [34] derived from a quantumchemically calculated potential energy surface that was refined taking evaluated experimental data [33] into account. We inspected J = 3 − 2 transition frequencies of the five lowest vibrational states and compared these with values derived from our second combined analysis.…”

“…We replaced the older ν 4 , ν 6 and ν 3 data with the new ones in order to evaluate the impact of these new data. We encountered massive labelling problems in that data set which have been discussed in a recent evaluation of experimental H 2 CS data [33]. Most mislabellings were encountered among the ν 4 and ν 6 at moderate and higher K a (≳ 2).…”

“…There have also been numerous quantum-chemical calculations on structural or vibrational properties of H 2 CS, in particular in the past 30 years [27][28][29][30][31][32]. The existing experimental rotational and rovibrational data were evaluated recently [33], and the results were employed in a refinement of a quantum-chemically generated potential energy surface to generate a hightemperature line list of H 2 CS [34]. We mention furthermore calculations of the properties of isomers of thioformaldehyde [35,36].…”

ExoMol line lists – XLVIII. High-temperature line list of thioformaldehyde (H2CS)

“…Of interest here is the infrared (IR) rotation-vibration (ro-vibrational) spectrum of H2CS, which has been the subject of numerous computational and experimental studies. Very recently, we performed a comprehensive analysis of the published experimental spectroscopic literature of H2CS (Mellor et al 2023) and extracted all meaningful transition data from 11 literature sources (Johnson & Powell 1970;Johns & Olson 1971;Beers et al 1972;Fabricant et al 1977;Bedwell & Duxbury 1980;Turner et al 1981;Mcnaughton & Bruget 1993;Clouthier et al 1994;Maeda et al 2008;Flaud et al 2008;Müller et al 2019). These data covered the ν1, ν2, ν3, ν4, ν5, ν6, and 2ν2 vibrational bands of H2CS and included transitions with rotational excitation up to J = 54, where J is the total angular momentum quantum number.…”

“…Because the PES utilised was essentially ab initio, the accuracy of the predicted fundamental wavenumbers was limited to around 1 to 2 cm −1 , which is not sufficient for spectroscopic applications. To substantially improve the accuracy of the computed line positions it is necessary to refine the PES to a set of empirical-quality energy levels such as the MARVEL H2CS dataset (Mellor et al 2023) discussed above. Doing so can lead to orders-of-magnitude improvements in the accuracy of the transition wavenumbers and this procedure has been undertaken for the present work.…”