Sub-Doppler millimetre-wave spectroscopy of DBS and HBS: accurate values of nuclear electric and magnetic hyperfine structure constants

Abstract

The unstable thioborine molecule and its deuterated variant have been produced by a high-temperature reaction between hydrogen sulfide and crystalline boron at 1100 degrees C in a flow system. Five rotational transitions from J = 2 <-- 1, to J = 6 <-- 5 have been recorded with sub-Doppler resolution for the vibrational ground state of H10/11BS and D10/11BS using the Lamb-dip technique. The hyperfine structure due to the electric quadrupole interaction of deuterium nucleus has been resolved yielding the first experimental determination of the deuterium quadrupole coupling constant in thioborine, which is 0.1403(75) MHz in D11 BS and 0.1360(38) MHz in D10BS. Fairly accurate values of 10/11B spin-rotation coupling constants and of the hydrogen-boron spin-spin coupling constants have also been determined. Additionally, the hyperfine structure of the rotational lines for the nu2 = 1 excited state has been investigated, thus obtaining information on the asymmetry of the electric field gradient at the B nucleus in the bending state.

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

“…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.…”