High-accuracy extrapolated ab initio thermochemistry.: III.: Additional improvements and overview

被引：234

作者：

Harding, Michael E. ^{[1
]}

Vazquez, Juana ^{[1
,2
]}

Ruscic, Branko ^{[3
]}

Wilson, Angela K. ^{[4
]}

Gauss, Juergen ^{[1
]}

Stanton, John F. ^{[2
]}

机构：

[1] Johannes Gutenberg Univ Mainz, Inst Phys Chem, D-55099 Mainz, Germany

[2] Univ Texas Austin, Inst Theoret Chem, Dept Chem & Biochem, Austin, TX 78712 USA

[3] Argonne Natl Lab, Chem Sci & Engn Div, Argonne, IL 60439 USA

[4] Univ N Texas, Dept Chem, Denton, TX 76203 USA

来源：

JOURNAL OF CHEMICAL PHYSICS | 2008年 / 128卷 / 11期

关键词：

D O I：

10.1063/1.2835612

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Effects of increased basis-set size as well as a correlated treatment of the diagonal Born-Oppenheimer approximation are studied within the context of the high-accuracy extrapolated ab initio thermochemistry (HEAT) theoretical model chemistry. It is found that the addition of these ostensible improvements does little to increase the overall accuracy of HEAT for the determination of molecular atomization energies. Fortuitous cancellation of high-level effects is shown to give the overall HEAT strategy an accuracy that is, in fact, higher than most of its individual components. In addition, the issue of core-valence electron correlation separation is explored; it is found that approximate additive treatments of the two effects have limitations that are significant in the realm of < 1 kJ mol(-1) theoretical thermochemistry. (c) 2008 American Institute of Physics.

引用

页数：15