The effects of higher orders of perturbation theory on the correlation energy of atoms and bonds in molecules

Autor(es)

Vincent, Mark A. ^{[1, 2]} ; Silva, Arnaldo F. ^{[1, 2]} ; McDonagh, James L. ^{[1, 2]} ; Popelier, Paul L. A. ^{[1, 2]}

Afiliação do(s) autor(es)

^[1] Univ Manchester, Manchester Inst Biotechnol, 131 Princess St, Manchester M1 7DN, Lancs - England

^[2] Univ Manchester, Sch Chem, Oxford Rd, Manchester M13 9PL, Lancs - England

• Tipo de documento: Artigo Científico
• Fonte: International Journal of Quantum Chemistry; v. 118, n. 8 APR 15 2018.
• Citações Web of Science: 7

Resumo

We examine, for the first time, the effects of higher orders of MOller-Plesset perturbation theory on the individual atoms within a molecule and the bonds between them, via the topological energy partitioning method of interacting quantum atoms. In real terms (i.e., not by absolute value) MP3 decreases the correlation energy of a bond, and MP4SDQ also decreases the energy of the atoms at either end of the bond. In addition, we investigated long-range through-space dispersive effects on a H-2 oligomer. Overall, MP3 is the largest correction to the correlation energy, and most of that energy is allocated to chemical bonds, reducing their values in actual terms. The MP4SDQ bond correlation correction, despite being relatively small, tends to have two effects: (i) for small or negative correlation energies MP4SDQ tends to decrease the bond correlation values even more, and (ii) for large (positive) bond correlation energies MP4SDQ tends to restore the bond correlation energies from the MP3 back toward the MP2 values. Furthermore, each individual part of a molecule or complex (atom or bond) has a specific convergence pattern for the MPn series: through-space interactions converge at MP2 but bonds converge at MP3 level. The atomic correlation energy appears to head toward convergence at the MP4 level. (AU)

• Processo FAPESP: 14/21241-9 - Inclusão de polarização na descrição de aminoácidos e peptídeos utilizando multipolos atômicos calculados a partir de densidades eletrônicas
• Beneficiário: Arnaldo Fernandes da Silva Filho
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 15/22247-3 - Utilizando a teoria quantum chemical Topology para a modelagem de campos de força para peptídeos através de densidades eletrônicas
• Beneficiário: Arnaldo Fernandes da Silva Filho
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Pós-Doutorado