title: Intermediate electrostatic field for the elongation method.
abstract: A simple way to improve the accuracy of the fragmentation methods is proposed. The formalism was applied to the elongation (ELG) method at restricted open-shell Hartree-Fock (ROHF) level of theory. The α-helix conformer of polyglycine was taken as a model system. The modified ELG method includes a simplified electrostatic field resulting from point-charge distribution of the system's environment. In this way the long-distance polarization is approximately taken into account. The field attenuates during the ELG process to eventually disappear when the final structure is reached. The point-charge distributions for each ELG step are obtained from charge sensitivity analysis (CSA) in force-field atoms resolution. The presence of the intermediate field improves the accuracy of ELG calculations. The errors in total energy and its kinetic and potential contributions are reduced by at least one-order of magnitude. In addition the SCF convergence of ROHF scheme is improved.
authors.affiliation: Department of Molecular and Material Sciences, Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan.
authors.forename: Piotr
authors.initials: P
authors.lastname: Kuźniarowicz
authors.forename: Kai
authors.initials: K
authors.lastname: Liu
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Aoki
authors.forename: Feng Long
authors.initials: FL
authors.lastname: Gu
authors.forename: Anna
authors.initials: A
authors.lastname: Stachowicz
authors.forename: Jacek
authors.initials: J
authors.lastname: Korchowiec