Mukarakate Calvin, Tao Chong, Jordan Christopher D, Polik William F, Reid Scott A
Department of Chemistry, Marquette University, Milwaukee, Wisconsin 53201-1881, USA.
J Phys Chem A. 2008 Jan 24;112(3):466-71. doi: 10.1021/jp077108m. Epub 2008 Jan 3.
We have recorded stimulated emission pumping (SEP) spectra of the A1A' ' 1A' system of CHF, which reveal rich detail concerning the rovibronic structure of the 1A' state up to approximately 7000 cm-1 above the vibrationless level. Using several intermediate A1A' ' state levels, we obtained rotationally resolved spectra for 16 of the 33 levels observed in our previous single vibronic level (SVL) emission study (Fan et al., J. Chem. Phys. 2005, 123, 014314), in addition to one new level. An anharmonic effective Hamiltonian model poorly reproduces the term energies even with the improved set of data because of the extensive interactions among levels in a given polyad (p) having combinations of nu1, nu2, nu3, which satisfy the relationship p = 2nu1 + nu2 + nu3. However, the precise A rotational constants determined from the SEP data were invaluable in clarifying the assignments for these strongly perturbed levels, and the data are well reproduced using a multiresonance effective Hamiltonian model. The derived vibrational parameters are in good agreement with high level ab initio calculations. The experimental frequencies were combined with those of CDF to derive a harmonic force field and average (rz,r(z)e) structures for the ground state.
我们记录了CHF的A1A' ' 1A' 系统的受激辐射泵浦（SEP）光谱，该光谱揭示了关于1A' 态的振转电子结构的丰富细节，直至高于无振动能级约7000 cm-1 。利用几个中间的A1A' ' 态能级，除了一个新能级外，我们还获得了在我们之前的单振子能级（SVL）发射研究（Fan等人，《化学物理杂志》，2005年，123卷，014314期）中观测到的33个能级中的16个能级的转动分辨光谱。即使使用改进后的数据，非谐有效哈密顿量模型也难以很好地再现能级能量，因为在给定的多重组（p）中，具有满足关系p = 2nu1 + nu2 + nu3的nu1、nu2、nu3组合的能级之间存在广泛的相互作用。然而，从SEP数据确定的精确A转动常数对于明确这些强扰动能级的归属非常重要，并且使用多共振有效哈密顿量模型可以很好地再现这些数据。推导得到的振动参数与高水平的从头计算结果吻合良好。将实验频率与CDF的频率相结合，得到了基态的谐性力场和平均（rz,r(z)e）结构。
