Derivatives of the approximated electrostatic potentials in unrestricted Hartree-Fock based on the fragment molecular orbital method and an application to polymer radicals

作者：Nakata Hiroya^*; Fedorov Dmitri G; Yokojima Satoshi; Kitaura Kazuo; Nakamura Shinichiro

来源：Theoretical Chemistry Accounts, 2014, 133(5): 1477.

DOI：10.1007/s00214-014-1477-6

• Solvation
• Analytic gradient
• SCZV
• HF calculation
• Macromolecules
• Polymer
• Molecular orbital calculations

The analytic energy gradient for the point charge approximation of the embedding potential is derived in the framework of unrestricted Hartree-Fock based on the fragment molecular orbital method (FMO). For this goal, we derive the necessary coupled-perturbed unrestricted Hartree-Fock equations, describing the response terms arising from the use of embedding atomic charges in dimer calculations. By a comparison to numerical gradients and with the aid of molecular dynamics, we show that the gradients have a high accuracy. A speed-up of the factor 7.3 is obtained for the largest system, when approximated potentials are used relative to the exact two-electron embedding. We apply the FMO method to polymer radicals and show that it has satisfactory accuracy in reproducing the geometries and energies of polymer radical reactions.

• 出版日期2014-3-30