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Computational models for proton transfer in biological systems
Author(s) -
Pardo Leonardo,
Mazurek Aleksander P.,
Osman Roman
Publication year - 1990
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560370508
Subject(s) - basis set , basis (linear algebra) , set (abstract data type) , chemistry , molecule , polarization (electrochemistry) , potential energy , proton , computational chemistry , transfer (computing) , atomic physics , physics , mathematics , computer science , quantum mechanics , geometry , density functional theory , organic chemistry , parallel computing , programming language
Abstract A computational scheme based on a “mixed basis set” approach is applied to the study of the structure and the energetics in proton transfer systems. Five hydrogen‐bonded systems of the type (CH 3 H n A ‥ H ‥ BH m CH 3 ) + , where A and B can be N, O, or S, have been investigated with various minimal and extended basis sets. Calculations with the extended basis set yield double‐well potential energy curves, which the minimal basis set is unable to reproduce. Calculations with the mixed basis set, constructed from an extended basis set on the atoms engaged in the hydrogen transfer part and a minimal basis set on the rest of the molecule, give predictions of geometries, potential energy curves, and relative energies similar to the results from the extended basis set. Inclusion of polarization functions in the mixed basis set becomes essential in systems that contain third row atoms. This scheme should become useful in studies of large molecules in which different parts can be represented at different levels of computational complexity.