计算有效核势积分的高效方法。

Efficient Method for Calculating Effective Core Potential Integrals.

作者信息

McKenzie Simon C, Epifanovsky Evgeny, Barca Giuseppe M J, Gilbert Andrew T B, Gill Peter M W

机构信息

Research School of Chemistry , Australian National University , Canberra , Australian Capital Territory 2601 , Australia.

Q-Chem Inc. , 6601 Owens Drive , Pleasanton , California 94588 , United States.

出版信息

J Phys Chem A. 2018 Mar 22;122(11):3066-3075. doi: 10.1021/acs.jpca.7b12679. Epub 2018 Mar 8.

DOI:10.1021/acs.jpca.7b12679

PMID:29465999

Abstract

Effective core potential (ECP) integrals are among the most difficult one-electron integrals to calculate due to the projection operators. The radial part of these operators may include r, r, and r terms. For the r terms, we exploit a simple analytic expression for the fundamental projected integral to derive new recurrence relations and upper bounds for ECP integrals. For the r and r terms, we present a reconstruction method that replaces these terms by a sum of r terms and show that the resulting errors are chemically insignificant for a range of molecular properties. The new algorithm is available in Q-Chem 5.0 and is significantly faster than the ECP implementations in Q-Chem 4.4, GAMESS (US) and Dalton 2016.

摘要

由于投影算符的存在，有效核势（ECP）积分是最难计算的单电子积分之一。这些算符的径向部分可能包含r、r和r项。对于r项，我们利用基本投影积分的一个简单解析表达式来推导ECP积分的新递推关系和上限。对于r和r项，我们提出一种重构方法，用r项的和来代替这些项，并表明对于一系列分子性质，由此产生的误差在化学上是微不足道的。新算法可在Q-Chem 5.0中使用，并且比Q-Chem 4.4、GAMESS（美国）和Dalton 2016中的ECP实现要快得多。