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Two‐step evaluation of binding energy and potential energy surface of van der Waals complexes
Author(s) -
Deshmukh Milind M.,
Sakaki Shigeyoshi
Publication year - 2012
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.21993
Subject(s) - van der waals force , van der waals radius , intermolecular force , van der waals strain , binding energy , van der waals surface , energy (signal processing) , ab initio , coupled cluster , cluster (spacecraft) , chemistry , van der waals molecule , physics , atomic physics , monomer , computational chemistry , crystallography , quantum mechanics , molecule , organic chemistry , computer science , programming language , polymer
Evaluation of intermolecular distance and binding energy (BE) of van der Waals complex/cluster at ab initio level of theory is computationally demanding when many monomers are involved. Starting from MP2 energy, we reached a two‐step evaluation method of BE of van der Waals complex/cluster through reasonable approximations; $ {\rm BE} = {\rm BE(HF)} +\sum _{{{\rm M}{i}}>{{\rm M}j}}\{{\rm BE}_{{{\rm M}i}-{{\rm M}j}}({\rm MP2} \ {\rm or} \ {\rm MP}2.5)-{\rm BE}_{{{\rm M}i}-{{M}j}}({\rm HF})\} $ where HF represents the Hartree‐Fock calculation, M i , M j , etc. are interacting monomers, and MP2.5 represents the arithmetic mean of MP2 and MP3. The first term is the usual BE of the complex/cluster evaluated at the HF level. The second term is the sum of the difference in two‐body BE between the correlated and HF levels of theory. This equation was applied to various van der Waals complexes consisting of up‐to‐four monomers at MP2 and MP2.5 levels of theory. We found that this method is capable of providing precise estimate of the BE and reproducing well the potential energy surface of van der Waals complexes/clusters; the maximum error of the BE is less than 1 kcal/mol and 1% in most cases except for several limited cases. The origins of error in these cases are discussed in detail. © 2012 Wiley Periodicals, Inc. J Comput Chem, 2012