Papousek D, Pracna P, Winnewisser M, Klee S, Demaison J
Zlicínská 18, Prague 6, 169 00, Czech Republic
J Mol Spectrosc. 1999 Aug;196(2):319-323. doi: 10.1006/jmsp.1999.7875.
A total of 4892 transition wavenumbers of the nu(2), nu(3), nu(5), and nu(6) fundamental bands of H(3)(12)CF and 1469 frequencies of the rotational transitions in the v(2) = 1, v(3) = 1, v(5) = 1, and v(6) = 1 vibrational states have been fitted simultaneously by taking explicitly into account various Coriolis interactions, l-type interactions, and alpha-resonance terms between and within the vibrational states. The standard deviation of the fit using 71 parameters was 8.10 x 10(-5) cm(-1) for the infrared data and 0.198 MHz for the rotational data. This study clearly shows that in order to obtain a really quantitative fit of the highly precise data of vibration-rotational and rotational spectroscopy, it is necessary to fit all the data simultaneously using a variational approach. The deperturbed values of the upper state rotational constants differ significantly from those obtained previously in fitting the nu(3) and nu(6) bands as isolated bands and the nu(2)/nu(5) bands by a variational approach. This is important for the precise determination of the equilibrium structure of methyl fluoride (J. Demaison, J. Breidung, W. Thiel, and D. Papousek, Struct. Chem., in press). Besides this, the results can be used in further studies of the reduced Hamiltonians for more complicated systems of interacting vibrational levels. Copyright 1999 Academic Press.
通过明确考虑振动态之间及内部的各种科里奥利相互作用、l 型相互作用和α共振项，对 H₃¹²CF 的 ν(2)、ν(3)、ν(5)和 ν(6)基频带的总共 4892 个跃迁波数以及 v(2)=1、v(3)=1、v(5)=1 和 v(6)=1 振动态中转动跃迁的 1469 个频率进行了同时拟合。使用 71 个参数进行拟合时，红外数据的标准偏差为 8.10×10⁻⁵ cm⁻¹，转动数据的标准偏差为 0.198 MHz。本研究清楚地表明，为了对振动 - 转动光谱和转动光谱的高精度数据进行真正定量的拟合，有必要使用变分方法同时拟合所有数据。上态转动常数的去微扰值与先前通过变分方法单独拟合 ν(3)和 ν(6)带以及 ν(2)/ν(5)带所获得的值有显著差异。这对于精确确定氟甲烷的平衡结构很重要（J. 德迈松、J. 布雷idung、W. 蒂尔和 D. 帕普塞克，《结构化学》，即将出版）。除此之外，这些结果可用于进一步研究相互作用振动态更复杂系统的简化哈密顿量。版权所有 1999 年学术出版社。
