Perturbation-dependent atomic orbitals for the calculation of spin-rotation constants and rotational g tensors
Perturbation-dependent atomic orbitals for the calculation of spin-rotation constants and rotational g tensors
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DOI：
10.1063/1.472143
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发表时间：
1996-08-15
影响因子：
4.4
通讯作者：
Helgaker, T
中科院分区：
文献类型：
--
作者：
Gauss, J;Ruud, K;Helgaker, T
自旋-转动常数和转动g张量可以分别作为能量对转动角动量和核自旋或角动量和外磁场的二阶导数来计算。为了克服这两个性质的量子化学计算中的慢基组收敛和非物理（规范）原点依赖性的问题，我们建议使用微扰相关的原子轨道（旋转伦敦轨道），它明确地依赖于角动量和外部磁场，是传统的伦敦轨道（也称为规范，包括原子轨道）的推广。结果表明，基于转动伦敦轨道的自旋转动常数和转动g张量的计算与核屏蔽和磁化率的伦敦轨道计算密切相关。在Hartree-Fock自洽场水平上对HF、N-2、CO和CH 2 O的测试计算表明，旋转伦敦轨道提供的基组极限具有上级的收敛性。他们认为，未来的计算采用旋转伦敦轨道与高度相关的波函数将能够提供前所未有的准确度的自旋旋转常数反旋转g张量的结果。(C)1996年美国物理学会。
Spin-rotation constants and rotational g tensors can be evaluated as second derivatives of the energy with respect to the rotational angular momentum and nuclear spin or angular momentum and external magnetic field, respectively. To overcome problems with the slow basis set convergence and the unphysical (gauge-)origin dependence in quantum chemical calculations of these two properties, we suggest the use of perturbation dependent atomic orbitals (rotational London orbitals), which depend explicitly on the angular momentum and the external magnetic field and are a generalization of the conventional London orbitals (also known as gauge-including atomic orbitals). It is shown that calculations of spin-rotation constants and rotational g tensors based on rotational London orbitals are closely related to London-orbital computations of nuclear shieldings and magnetizabilities. Test calculations at the Hartree-Fock self-consistent-field level for HF, N-2, CO, and CH2O demonstrate the superior convergence to the basis set limit provided by the rotational London orbitals. They suggest that future calculations employing rotational London orbitals in conjunction with highly correlated wave functions will be able to provide results of unprecedented accuracy for spin-rotation constants anti rotational g tensors. (C) 1996 American Institute of Physics.