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Outlying Charge, Stability, Efficiency, and Algorithmic Enhancements in the Quantum‐Mechanical Solvation Method, COSab‐GAMESS
Author(s) -
Gregerson Laura N.,
Baldridge Kim K.
Publication year - 2003
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.200390340
Subject(s) - chemistry , solvation , density functional theory , quantum , computation , charge (physics) , statistical physics , computational chemistry , molecule , algorithm , computer science , quantum mechanics , physics , organic chemistry
In this work, we present algorithmic modifications and extensions to our quantum‐mechanical approach for the inclusion of solvent effects by means of molecule‐shaped cavities. The theory of conductor‐like screening, modified and extended for quantum‐mechanical techniques, serves as the basis for our solvation methodology. The modified method is being referred to as COSab‐GAMESS and is available within the GAMESS package. Our previous work has emphasized the implementation of this model by way of a distributed multipole approach for handling the effects of outlying charge. The method has been enabled within the framework of open‐ and closed‐shell RHF and MP2. In the present work, we present a ) a second method to handle outlying charge effects, b ) algorithmic extensions to open‐ and closed‐shell density‐functional theory, second‐derivative analysis, and reaction‐path following, and c ) enhancements to improve performance, convergence, and predictability. The method is now surtable for large molecular systems. New features of the enhanced continuum model are highlighted by means of a set of neutral and charged species. Computations on a series of structures with roughly the same molecular shape and volume provides an evaluation of cavitation effects.