Generic implementation of semi-analytical CI gradients for NDDO-type methods
Generic implementation of semi-analytical CI gradients for NDDO-type methods
复制标题
NDDO 类型方法的半解析 CI 梯度的通用实现
DOI：
--
复制
发表时间：
2005
期刊：
影响因子：
--
通讯作者：
W. Thiel
中科院分区：
文献类型：
--
作者：
S. Patchkovskii;A. Koslowski;W. Thiel
通过使用数值积分和Fock矩阵导数，在构型相互作用（CI）和其他非变分处理的解析方法的背景下，推导并实现了ndo型方法的一般半解析能量梯度。通过与全数值计算和全解析计算的比较，确定了这种混合方法的正确性、数值精度和性能。CI梯度的半解析计算通常比完全数值计算快得多，但比完全解析计算慢一些，但表现出相同的缩放行为。它是选择的方法，每当一个完全解析CI梯度是不可用的，由于缺乏解析积分导数。这个实现是泛型的，因为它可以很容易地扩展到任何新的nddo类型的哈密顿量。目前半解析CI梯度的发展将促进电子激发态的研究与最近提出的NDDO方法，包括正交校正。
Generic semi-analytical energy gradients are derived and implemented for NDDO-type methods, by using numerical integral and Fock matrix derivatives in the context of an otherwise analytical approach for configuration interaction (CI) and other non-variational treatments. The correctness, numerical precision, and performance of this hybrid approach are established through comparisons with fully numerical and fully analytical calculations. The semi-analytical evaluation of the CI gradient is generally much faster than the fully numerical computation, but somewhat slower than a fully analytical calculation, which however shows the same scaling behavior. It is the method of choice whenever a fully analytical CI gradient is not available due to the lack of analytical integral derivatives. The implementation is generic in the sense that it can easily be extended to any new NDDO-type Hamiltonian. The present development of a semi-analytical CI gradient will facilitate studies of electronically excited states with recently proposed NDDO methods that include orthogonalization corrections.