Study on the construction of satisfactory nonorthogonal localized molecular orbitals

作     者：FENG Huasheng BIAN Jiang LI Lemin 

作者机构：State Key Laboratory of Rare Earth Materials and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 China State Key Laboratory of Rare Earth Materials and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 China State Key Laboratory of Rare Earth Materials and Applications College of Chemistry and Molecular Engineering Peking University Beijing 100871 China 

出 版 物：《Science China Chemistry》 (中国科学（化学英文版）)

年 卷 期：2004年第47卷第1期

页      面：1-9页

核心收录：

学科分类：07[理学] 0703[理学-化学] 

基　　金：This work was supported by the National Natural Science Foundation of China(Grant Nos.29928002 20333020) 

主　　题：quantum chemical calculation, chemical bonding, nonorthogonal localized molecular orbital, orbital spread. 

摘      要：Comparing to orthogonal localized molecular orbitals (OLMO), the nonorthogonal localized molecular orbitals (NOLMO) exhibit bonding pictures more accordant with those in the traditional chemistry. They are more contracted, so that they have a better transferability and better performances for the calculation of election correlation energies and for the linear scaling algorithms of large systems. The satisfactory NOLMOs should be as contracted as possible while their shapes and spatial distribution keep in accordance with the traditional chemical bonding picture. It is found that the spread of NOLMOs is a monotonic decreasing function of their orthogonality, and it may reduce to any extent as the orthogonality descends. However, when the orthogonality descends to some point, the shapes and spatial distribution of the NOLMOs deviate drastically from the traditional chemical bonding picture, and finally the NOLMOs tend to linear dependence. Without the requirement of orthogonalization, some other constraints have to be imposed for constructing satisfactory NOLMOs by minimizing their spread functional. It is shown that satisfactory results can be generated by coupling the minimization of orbital spread functionals with the maximization of the distances between orbital centroids.