Dore L, Puzzarini C, Cazzoli G, Gambi A
Dipartimento di Chimica "G. Ciamician,", Università di Bologna, Via Selmi 2, Bologna, I-40126, Italy
J Mol Spectrosc. 2000 Dec;204(2):262-267. doi: 10.1006/jmsp.2000.8216.
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)ClHC&dbond;CFH and of the 19(9,10/11) and 17(10,7/8) levels of (37)ClHC&dbond;CFH cause strong perturbations of the hyperfine patterns and give rise to perturbation-allowed DeltaJ = 2 and DeltaJ = 3 transitions. Lamb-dip measurements of such perturbed hyperfine patterns and of forbidden DeltaJ = +2 and perturbation-enhanced DeltaJ = 0 transitions of (35)ClHC&dbond;CFH provided an accurate determination of chi(ab), the off-diagonal element of the inertial nuclear quadrupole tensor. For (37)ClHC&dbond;CFH, chi(ab) was determined for the first time thanks to the observation of perturbed hyperfine patterns and of forbidden DeltaJ = +3 and DeltaJ = -2 transitions. Additional measurements of hyperfine structures led to improved values for the diagonal elements of the chi 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. Copyright 2000 Academic Press.
在毫米波区域，对含有（35）Cl和（37）Cl的顺式-1-氯-2-氟乙烯同分异构体的转动跃迁中的核四极超精细结构进行了测量。（35）ClHC≡CFH的9（3,7）和10（2,9）能级以及（37）ClHC≡CFH的19（9,10/11）和17（10,7/8）能级的近简并导致超精细模式的强烈扰动，并产生允许的ΔJ = 2和ΔJ = 3跃迁。对（35）ClHC≡CFH的这种受扰动超精细模式以及禁戒的ΔJ = +2和受扰动增强的ΔJ = 0跃迁进行兰姆凹陷测量，提供了对惯性核四极张量非对角元素χ(ab)的精确测定。对于（37）ClHC≡CFH，由于观察到受扰动的超精细模式以及禁戒的ΔJ = +3和ΔJ = -2跃迁，首次确定了χ(ab)。对超精细结构的额外测量得到了（35）Cl和（37）Cl的χ张量对角元素的改进值。此外，通过使用多组态自洽场（MCSCF）方法并采用三重ζ质量的基组计算氯核处的场梯度，评估了完整的惯性核四极张量：与实验结果取得了很好的一致性。版权所有2000年学术出版社。
