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2874428 
Journal Article 
Covalent Bond Fragmentation Suitable To Describe Solids in the Fragment Molecular Orbital Method 
Fedorov, DG; Jensen, J; Deka, RC; Kitaura, K 
2008 
1 
Journal of Physical Chemistry A
ISSN: 1089-5639
EISSN: 1520-5215 
112 
46 
11808-11816 
English 
18942816 
WOS:000260926700034 
To improve the accuracy of the fragment molecular orbital method (FMO), we introduce a new fragmentation scheme based on using frozen orbitals to describe fractioned bonds. By applying this scheme to a set of polyalanine systems of up to 40 residues for the alpha-helix and beta-strand isomers, we established its accuracy, which is considerably improved compared to the original hybrid orbital projection method used for detaching bonds in FMO. For instance, at the two-body FMO expansion with the 6-311G* basis set, the error was typically reduced 2-4 times, and for 6-31G* the accuracy increase was even larger (10 times in terms of the maximum error). For the Trp-cage protein (PDB file 1L2Y) with many charged residues, a fairly large error was observed, which was shown to become small with a larger fragment size or at the three-body level. Consequently, we applied the new scheme to the adsorption of toluene and phenol on a faujasite zeolite, and we demonstrated that good accuracy can be achieved in reproducing ab initio results.