On the Interfragment Exchange in the X-Pol Method

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• 作者：Alessandro Cembran ; Peng Bao ; Yingjie Wang ; Lingchun Song ; Donald G. Truhlar ; Jiali Gao
• 刊名：Journal of Chemical Theory and Computation
• 出版年：2010
• 出版时间：August 10, 2010
• 年：2010
• 卷：6
• 期：8
• 页码：2469-2476
• 全文大小：211K
• 年卷期：v.6,no.8(August 10, 2010)
• ISSN：1549-9626

文摘

The inclusion of exchange repulsion terms in the explicit polarization (X-Pol) model is examined by antisymmetrizing the X-Pol Hartree product wave function; this yields X-Pol with full eXchange, called X-Pol-X. When the monomers are treated by Hartree−Fock theory, this calculation can be accomplished by using the formalism of block-localized wave functions (BLW) that has been used in a variety of applications. In this case the block-localized structure in the X-Pol-X wave function allows for decomposition of the full Fock matrix of a dimension of M blocks into M smaller Fock matrices. The method is illustrated by considering two trimer structures of water clusters, and it is found that the total exchange repulsion energies in these hydrogen-bonding test cases are adequately treated and—to a good approximation—are pairwise additive. We also present a formalism to yield a simplified Fock matrix by making use of the neglect of interfragment differential overlap (NIDO) approximation, which is less severe than the neglect of diatomic differential overlap (NDDO) approximation.