Analysis of the Complex Quadrupole Hyperfine Patterns for Two Chlorine Nuclei in the Rotational Spectrum of 2,5-Dichlorothiophene
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Date
2021-07-13
Authors
Daudet, Gabrielle
van Wijngaarden, Jennifer
Journal Title
Journal ISSN
Volume Title
Publisher
The Journal of Physical Chemistry A
Abstract
The rotational spectrum of 2,5-dichlorothiophene (DCT) was measured for the first time using Fourier transform microwave spectroscopy from 5.5-19 GHz. Dense hyperfine splitting patterns due to the two quadrupolar chlorine nuclei (I=3/2) were resolved and assigned for the 35Cl-35Cl, 37Cl-35Cl and 37Cl-37Cl isotopologues as well as for the two 13C and one 34S analogs with two 35Cl atoms allowing derivation of their respective nuclear quadrupole coupling tensors. The rotational constants obtained from fitting the spectra of the six isotopic species allowed derivation of the experimental geometry of DCT for comparison with the equilibrium structure computed at the MP2/aug-cc-pVTZ level. This revealed that the electron withdrawing effect of chlorine causes small distortions to the ring geometry relative to thiophene including a 1.1o increase in the two S-C-C angles and a 0.012 Å increase to the two S-C bonds.
Description
Keywords
microwave spectroscopy, structure determination, hyperfine structure, quadrupole coupling constant, quantum chemistry calculations
Citation
Daudet, G.; van Wijngaarden, J. Analysis of the Complex Quadrupole Hyperfine Patterns for Two Chlorine Nuclei in the Rotational Spectrum of 2,5-Dichlorothiophene. J. Phys. Chem. A 2021, 125, 28, 6089–6095