Tellgren Erik I, Soncini Alessandro, Helgaker Trygve
Centre for Theoretical and Computational Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway.
J Chem Phys. 2008 Oct 21;129(15):154114. doi: 10.1063/1.2996525.
A self-consistent field (SCF) London-orbital computational scheme to perform gauge-origin independent nonperturbative calculations for molecules in strong magnetic fields is presented. The crucial difference in the proposed approach with respect to common-origin finite-field SCF implementations consists in the evaluation of molecular integrals over the field-dependent molecular basis functions, which is tantamount to computing molecular integrals in a hybrid Gaussian and plane-wave basis set. The implementation of a McMurchie-Davidson scheme for the calculation of the molecular integrals over London orbitals is discussed, and preliminary applications of the newly developed code to the calculation of fourth-rank hypermagnetizabilities for a set of small molecules, benzene, and cyclobutadiene are presented. The nonperturbative approach is particularly useful for studying the highly nonlinear response of paramagnetic closed-shell systems such as boron monohydride, or the pi-electron response of cyclobutadiene.
提出了一种自洽场（SCF）伦敦轨道计算方案，用于对强磁场中的分子进行与规范原点无关的非微扰计算。所提出的方法与普通原点有限场SCF实现的关键区别在于对依赖于场的分子基函数进行分子积分的评估，这等同于在混合高斯和平坦波基组中计算分子积分。讨论了用于计算伦敦轨道上分子积分的McMurchie-Davidson方案的实现，并展示了新开发代码对一组小分子、苯和环丁二烯的四阶超磁化率计算的初步应用。这种非微扰方法对于研究顺磁闭壳系统（如氢化硼）的高度非线性响应或环丁二烯的π电子响应特别有用。
