Premium
A combined freeze‐and‐cut strategy for the description of large molecular systems using a localized orbitals approach
Author(s) -
Borini Stefano,
Maynau Daniel,
Evangelisti Stefano
Publication year - 2005
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.20236
Subject(s) - atomic orbital , complete active space , ab initio , molecular orbital , localized molecular orbitals , space (punctuation) , field (mathematics) , computational chemistry , molecule , chemistry , physics , molecular orbital theory , molecular physics , quantum mechanics , computer science , mathematics , pure mathematics , electron , operating system
A technique to reduce the computational effort in calculating ab initio energies using a localized orbitals approach is presented. By exploiting freeze strategy at the self‐consistent field (SCF) level and a cut of the unneeded atomic orbitals, it is possible to perform a localized complete active space (CAS‐SCF) calculation on a reduced system. This will open the possibility to perform ab initio treatments on very large molecular systems, provided that the chemically important phenomena happen in a localized zone of the molecule. Two test cases are discussed, to illustrate the performance of the method: the cis–trans interconversion curves for the (7Z)‐13 ammoniotridec‐7‐enoate, which demonstrates the ability of the method to reproduce the interactions between charged groups; and the cisoid–transoid energy barrier for the aldehydic group in the C 13 polyenal molecule. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 1042–1051, 2005