title: A multicentered approach to integrated QM/QM calculations. Applications to multiply hydrogen bonded systems.
abstract: A multicentered integrated QM/QM technique has been developed. By separating high-level calculations in distinct regions of molecules, the multicentered approach supplants a single large high-level calculation with several smaller calculations. Due to the steep polynomial scaling of traditional ab initio quantum chemical methods, this separation significantly enhances the computational efficiency of QM/QM methods. The straightforward implementation of this multicentered approach is illustrated with several large poly-alcohols that form hydrogen bonds with water. The largest alcohol-water complex contains 81 atoms. For properly selected model systems, this multicentered approach introduces essentially no error in the dissociation energies of these complexes relative to conventional QM/QM schemes. This multicentered technique should be easily extended to other, more general integrated methods (QM/MM, ONIOM, etc).
authors.affiliation: Department of Chemistry and Biochemistry, University of Mississippi, University, Mississippi 38677-1848.
authors.forename: Brian W
authors.initials: BW
authors.lastname: Hopkins
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Tschumper