Insufficient description of dispersion in B3LYP and large basis set superposition errors in MP2 calculations can hide peptide conformers

被引：113

作者：

Holroyd, Leo F.

van Mourik, Tanja

机构：

[1] Univ St Andrews, Sch Chem, St Andrews KY16 9ST, Fife, Scotland

[2] UCL, Dept Chem, London WC1H 0AJ, England

来源：

CHEMICAL PHYSICS LETTERS | 2007年 / 442卷 / 1-3期

基金：

英国工程与自然科学研究理事会;

关键词：

D O I：

10.1016/j.cplett.2007.05.072

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：

B3LYP/6-31+G(d) and MP2/6-31+G(d) calculations predict markedly different structures for one Tyr-Gly conformer. Calculation of the energy profile for rotation around the glycine C-alpha-N bond reveals one minimum in the B3LYP profile (phi(gly) = 180 degrees) and two in the MP2 profile (similar to 75 degrees and 280 degrees). Large intramolecular BSSE values are responsible for masking the 180 degrees-minimum in the MP2 profile: approximate elimination of BSSE in the MP2 calculations - by (1) correction using BSSE values from complexes of phenol and N-formylglycine, (2) the application of local MP2, or (3) employing large basis sets (aug-cc-pVTZ/QZ) and density fitting - yields an unambiguous triple-well potential. (C) 2007 Elsevier B.V. All rights reserved.

引用

页码：42 / 46

页数：5

共 34 条

[1] Exchange-hole dipole moment and the ospersion interaction [J].