Nuclear Quadrupole Tensors for 35Cl and 37Cl in cis-1-chloro-2-fluoroethylene Obtained by Detection of Perturbation-Allowed ΔJ = 2 and ΔJ = 3 Transitions
✍ Scribed by Luca Dore; Cristina Puzzarini; Gabriele Cazzoli; Alberto Gambi
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 144 KB
- Volume
- 204
- Category
- Article
- ISSN
- 0022-2852
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✦ Synopsis
The nuclear quadrupole hyperfine structure in rotational transitions of cis-1-chloro-2-fluoroethylene was measured for both 35 Cl and 37 Cl containing isotopomers in the millimeter-wave region. Near degeneracies of the 9 3,7 and 10 2,9 levels of 35 ClHCACFH and of the 19 9,10/11 and 17 10,7/8 levels of 37 ClHCACFH cause strong perturbations of the hyperfine patterns and give rise to perturbation-allowed ⌬J ϭ 2 and ⌬J ϭ 3 transitions. Lamb-dip measurements of such perturbed hyperfine patterns and of forbidden ⌬J ϭ ϩ2 and perturbation-enhanced ⌬J ϭ 0 transitions of 35 ClHCACFH provided an accurate determination of ab , the off-diagonal element of the inertial nuclear quadrupole tensor. For 37 ClHCACFH, ab was determined for the first time thanks to the observation of perturbed hyperfine patterns and of forbidden ⌬J ϭ ϩ3 and ⌬J ϭ Ϫ2 transitions. Additional measurements of hyperfine structures led to improved values for the diagonal elements of the tensor of both 35 Cl and 37 Cl. Moreover, the complete inertial nuclear quadrupole tensor was evaluated from the field gradient at the chlorine nucleus computed by using the Multi-Configuration Self-Consistent Field (MCSCF) approach and employing basis sets of triple-zeta quality: very good agreement with the experiment was obtained.