Comparison with ab initio theoretical calculations
Comparison with ab initio theoretical calculations
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发表时间：
1996
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通讯作者：
L. B. Knight;R. Babb;M. Ray;T. J. Banisaukas
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作者：
L. B. Knight;R. Babb;M. Ray;T. J. Banisaukas
首次报道了VO2自由基的光谱表征以及VO的新结果，并对VO3和V21进行了初步的归属。利用常规的高温蒸发和脉冲激光烧蚀产生方法，用电子自旋共振技术研究了这些钒自由基在Ne基质中的电子自旋共振光谱。对VO2的详细ESR研究表明，它是A1基态的非线性；g张量分析揭示了激发电子态的存在~B1！大约比基态高1 eV。这个激发态的预言和观测到的核超精细相互作用~A张量！V和O的计算结果与各种从头计算方法得到的理论结果进行了比较。在包括UHF、ROHF、CAS-SCF和MR-SDCI~多参考单双组态相互作用在内的不同理论水平上进行了扩展基组从头算计算。虽然UHF对超精细相互作用的计算有很大的误差，但较好的理论水平给出了与实验定性一致的结果，并为解释提供了帮助。VO2被预测为bentA1态，与具有主要在V3d轨道上的奇电子的线性D构型相关。VO_3被预测为平面C_2v，AB2轨道中的奇电子定域在氧的平面n型p轨道上。©1996美国物理研究所。@S0021-9606~96 03047-4#
The first spectroscopic characterization of the VO 2 radical is reported along with new results for VO and tentative assignments for the VO 3 and V2 1 radicals. These vanadium radicals were investigated in neon matrices a t 4 K by electron spin resonance utilizing conventional high temperature vaporization and pulsed laser ablation generation methods. A detailed ESR study of VO2 showed it to be nonlinear with a A1 ground state; theg tensor analysis reveals the presence of an excited electronic state ~B1! approximately 1 eV above the ground state. This excited state prediction and the observed nuclear hyperfine interactions ~A tensors! for V and O were compared with theoretical results obtained from various ab initio computational methods. Ab initio calculations with an extended basis set were performed at various levels of theory including UHF, ROHF, CAS-SCF, and MR-SDCI ~multireference single and double configuration interaction !. While UHF calculations of the hyperfine interaction were grossly in error, the better levels of theory gave qualitative agreement with experiment and provided an aid to interpretation. VO 2 is predicted to be a bentA1 state, correlating with the linear D configuration having the odd electron predominantly in the V 3d orbital. VO3 is predicted to be planar C2v, with the odd electron in ab2 orbital localized in the oxygen in-plane n-type p orbitals. © 1996 American Institute of Physics. @S0021-9606 ~96!03047-4#