Exploration of basis set issues for calculation of intermolecular interactions.
Exploration of basis set issues for calculation of intermolecular interactions.
复制标题
探索计算分子间相互作用的基组问题。
DOI：
10.1021/jp0680239
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发表时间：
2006
期刊：
影响因子：
--
通讯作者：
E. Bernstein
中科院分区：
文献类型：
--
作者：
E. Jakubikova;A. Rappé;E. Bernstein
分子间相互作用的从头计算需要一个大的基集来准确地描述具有显性色散相互作用的系统。本文着重讨论了用超分子方法计算弱束缚体系的分子间键能，以及计算基集的选择问题，特别是基集的大小、二电子积分码的效率、基集叠加误差（BSSE）和基函数的线性依赖性。为了寻找更有效的计算分子间相互作用的基集，标准基集（10s Huzinaga, 6-311G**, cc-pV6Z），或它们的部分，被一组偏心的，s或p函数扩展（镶嵌），对称地放置在原子核周围。标准基集（10s Huzinaga, 6- 311g **, cc-pVXZ, aug-cc-pVXZ, X = D， T， Q, 5,6）也被原子中心的高角动量函数集（p， D, f）扩充。在理论的MP2或UCCSD水平上，优化了镶嵌函数与原子核的距离以及镶嵌函数和增强函数的轨道指数。在具有优势色散相互作用(3)H(2)、（CH(4)）(2)和Ne(2)的模型系统上对这两种方法进行了测试，并比较了它们的效率。镶嵌和增强都成功地描述了这些模型系统的分子间相互作用，增强更有效。我们的研究结果引起了人们对精确计算中不可避免地存在的线性依赖问题的关注，并证实了底层标准基集的必要性，这些基集提供了对核心和价电子的良好描述，以使镶嵌和增强方法可靠。
The ab initio calculation of intermolecular interactions requires a large basis set to describe systems with dominant dispersion interaction accurately. This paper focuses on calculation of intermolecular bonding energies of weakly bound systems within the supermolecular method and on issues related to the choice of a basis set for these calculations, in particular size of the basis set, efficiency of 2-electron integral codes, basis set superposition error (BSSE), and the linear dependence of basis functions. In an attempt to find more efficient basis sets for calculations of intermolecular interactions, standard basis sets (10s Huzinaga, 6-311G**, cc-pV6Z), or their parts, are extended (tessellated) by a set of off-centered, s or p functions, symmetrically placed around the nuclei. Standard basis sets (10s Huzinaga, 6-311G**, cc-pVXZ, aug-cc-pVXZ, X = D, T, Q, 5, 6) are also augmented by sets of atom-centered, higher angular momentum functions (p, d, f). The distance from the nucleus of tessellating functions and orbital exponents of tessellating and augmenting functions are optimized with respect to the BSSE-corrected bonding energy at the MP2 or UCCSD level of theory. The two approaches are tested on the model systems with dominant dispersion interactions (3)H(2), (CH(4))(2), and Ne(2), and their efficiency is compared. Both tessellation and augmentation are successful in describing the intermolecular interactions of these model systems, with augmentation being more efficient. Our results draw attention to the linear dependence problems inevitably present in accurate calculations and confirm the need for underlying standard basis sets that provide good descriptions of core and valence electrons for the tessellation and augmentation approaches to be reliable.