A Treatment of the Renner Effect Using the MORBID Hamiltonian
A Treatment of the Renner Effect Using the MORBID Hamiltonian
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DOI：
10.1006/jmsp.1995.1101
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发表时间：
1995-05
影响因子：
1.4
通讯作者：
P. Jensen;M. Brumm;W. Kraemer;P. Bunker
中科院分区：
文献类型：
--
作者：
P. Jensen;M. Brumm;W. Kraemer;P. Bunker
摘要对于三原子分子，我们导出了在两个势能面在线性组态接触的情况下，确定其能级和波函数所必需的振子哈密顿量、基函数和矩阵元。由于电子角动量的影响（伦纳效应），转动电子能级的计算变得复杂，在处理这个问题时，我们考虑了自旋-轨道耦合。我们已经编写了一个计算机程序来实现这个过程。我们的方法基于孤立电子态的MORBID哈密顿量和计算机程序[P.詹森，J. Mol.光谱128，478 - 501（1988）; J. Chem. Soc.法拉第trans.2 84，1315 - 1340（1988）;在"计算分子物理学方法"（S. Wilson和G. H. F. Diercksen，Eds.），Plenum出版社，纽约，1992年]。该方法导致一个非常有效的计算过程，将在未来，使我们能够拟合数据，以确定势能面和自旋轨道耦合函数。本文根据W. W.的从头算数据，通过计算亚甲基自由基CH2的a1 A1和B 1 B 1电子态的振子能，对实现新方法的计算机程序进行了检验。H.小绿色，n. C. Handy，P. J. Knowles，和S. Carter [J.Chem.Phys.94，118 - 132（1991）]的结果，并将我们的结果与这些作者得到的振子能量值进行比较。我们还报告了振动（即，J = 0）的能量，这些能量是根据P.詹森和P.R.掩体[J. Chem. Phys. 89，1327 - 1332（1988）]。这些电子振动能量和从拟合的a态势确定的MORBID结果之间的比较对Dai及其同事先前对a态线性势垒的估计提出了重大质疑[见G. V.哈特兰，D. Qin和H. - L. Dal，J.Chem.Phys.98，2469 - 2472（1993）和其中的参考文献]。最后，我们构建了定量的相关图，显示了旋转振动能量的变化作为调整的势能面从线性弯曲。
Abstract For a triatomic molecule, we develop the rovibronic Hamiltonian, basis functions, and matrix elements necessary to allow us to determine the energy levels and wavefunctions in the situation that two potential energy surfaces touch at the linear configuration. The calculation of the rovibronic energy levels is complicated by the effect of the electronic angular momentum (the Renner effect), and while dealing with this problem we include spin-orbit coupling. We have written a computer program to implement the procedure. We base our approach on the MORBID Hamiltonian and computer program for an isolated electronic state [P. Jensen, J. Mol. Spectrosc. 128, 478-501 (1988); J. Chem. Soc. Faraday Trans. 2 84, 1315-1340 (1988); in "Methods in Computational Molecular Physics" (S. Wilson and G. H. F. Diercksen, Eds.), Plenum Press, New York, 1992]. The approach leads to a very efficient computational procedure that will, in the future, allow us to make fittings to data in order to determine potential energy surfaces and spin-orbit coupling functions. In this paper we test the computer program implementing the new procedure by calculating rovibronic energies for the a 1 A 1 and b 1 B 1 electronic states of the methylene radical CH 2 on the basis of ab initio data by W. H. Green, Jr., N. C. Handy, P. J. Knowles, and S. Carter [ J. Chem. Phys. 94, 118-132 (1991)] and comparing our results with the rovibronic energy values obtained by these authors. We also report vibronic (i.e., J = 0) energies determined on the basis of a fitted potential for the a 1 A 1 state by P. Jensen and P. R. Bunker [ J. Chem. Phys. 89, 1327-1332 (1988)]. Comparison between these vibronic energies and MORBID results determined from the fitted a-state potential throws significant doubt on previous estimations of the a-state barrier to linearity by Dai and co-workers [see G. V. Hartland, D. Qin, and H.-L. Dal, J. Chem. Phys. 98, 2469-2472 (1993) and references therein]. Finally, we construct quantitative correlation diagrams showing how the rovibronic energies change as the potential energy surfaces are adjusted from linear to bent.