Rácsai Balázs, Ferenc Dávid, Margócsy Ádám, Mátyus Edit
ELTE, Eötvös Loránd University, Institute of Chemistry, Pázmány Péter Sétány 1/A, Budapest H-1117, Hungary.
J Chem Phys. 2024 Jun 7;160(21). doi: 10.1063/5.0213079.
Drachmann's regularization approach is implemented for floating explicitly correlated Gaussians (fECGs) and molecular systems. Earlier applications of drachmannized relativistic corrections for molecular systems were hindered due to the unknown analytic matrix elements of 1/rix1/rjy-type operators with fECGs. In the present work, one of the 1/r factors is approximated by a linear combination of Gaussians, which results in calculable integrals. The numerical approach is found to be precise and robust over a range of molecular systems and nuclear configurations, and thus, it opens the route toward an automated evaluation of high-precision relativistic corrections over potential energy surfaces of polyatomic systems. Furthermore, the newly developed integration approach makes it possible to construct the matrix representation of the square of the electronic Hamiltonian relevant for energy lower-bound as well as time-dependent computations of molecular systems with a flexible and high-precision fECG basis representation.
德拉赫曼正则化方法应用于显式浮动相关高斯函数（fECGs）和分子体系。早期将德拉赫曼化相对论修正应用于分子体系时，由于1/rix1/rjy型算符与fECGs的解析矩阵元未知而受到阻碍。在本工作中，其中一个1/r因子由高斯函数的线性组合近似，这使得积分可计算。该数值方法在一系列分子体系和核构型范围内被发现是精确且稳健的，因此，它为在多原子体系势能面上自动评估高精度相对论修正开辟了道路。此外，新开发的积分方法使得能够构建与能量下限相关的电子哈密顿量平方的矩阵表示，以及用于具有灵活且高精度fECG基表示的分子体系的含时计算。
