Balabin Roman M
Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland.
J Chem Phys. 2008 Oct 28;129(16):164101. doi: 10.1063/1.2997349.
In this paper, an extra error source for high-quality ab initio calculation of conformation equilibrium in normal alkanes-intramolecular basis set superposition error (BSSE)-is discussed. Normal butane (n-butane) and normal hexane (n-hexane) are used as representative examples. Single-point energy difference and BSSE values of trans and gauche conformations for n-butane (and trans-trans-trans and gauche-gauche-gauche conformations for n-hexane) were calculated using popular electron correlation methods: The second-order Moller-Plesset (MP2), the fourth-order Moller-Plesset (MP4), and coupled cluster with single and double substitutions with noniterative triple excitation [CCSD(T)] levels of theory. Extrapolation to the complete basis set is applied. The difference between BSSE-corrected and uncorrected relative energy values ranges from approximately 100 cal/mol (in case of n-butane) to more than 1000 cal/mol (in case of n-hexane). The influence of basis set type (Pople or Dunning) and size [up to 6-311G(3df,3pd) and aug-cc-pVQZ] is discussed.
本文讨论了在正构烷烃构象平衡的高质量从头计算中一个额外的误差来源——分子内基组重叠误差（BSSE）。以正丁烷和正己烷作为代表性实例。使用流行的电子相关方法计算了正丁烷反式和顺式构象（以及正己烷反-反-反式和顺-顺-顺式构象）的单点能量差和BSSE值：二阶莫勒-普列斯特定理（MP2）、四阶莫勒-普列斯特定理（MP4）以及含单双取代和非迭代三激发的耦合簇理论[CCSD(T)]水平。应用了对完整基组的外推。经BSSE校正和未经校正的相对能量值之间的差异范围从大约100卡/摩尔（正丁烷的情况）到超过1000卡/摩尔（正己烷的情况）。讨论了基组类型（波普尔或邓宁）和大小[直至6-311G(3df,3pd)和aug-cc-pVQZ]的影响。
