Empirical corrections in the G3X and G3X(CCSD) theories combined with a compact effective pseudopotential

Author(s)

Silva, Cleuton de Souza ^{[1, 2]} ; Custodio, Rogerio ^[2]

Affiliation

^[1] Univ Fed Amazonas, Inst Ciencias Exatas & Tecnol, Campus Itacoatiara, BR-69100021 Itacoatiara, Amazonas - Brazil

^[2] Univ Estadual Campinas, Inst Quim, POB 6154, BR-13083970 Campinas, SP - Brazil

• Document type: Journal article
• Source: THEORETICAL CHEMISTRY ACCOUNTS; v. 137, n. 2 JAN 25 2018.
• Web of Science Citations: 4

Abstract

The G3X-CEP and G3X(CCSD)-CEP composite methods were developed by combining a compact effective pseudopotential (CEP) with the G3X and G3X(CCSD) all-electron methods. The G3/05 test set was used as reference data to analyze the performance of these methods by calculating enthalpies of formation, ionization energies, electron affinities, proton affinities, and molecular atomization energies. Tests were carried out considering different numbers of higher-level correction (HLC) parameters as well as a scaling of the experimental atomization energies of the elements used to determine the enthalpies of formation. The overall behavior of G3X-CEP and G3X(CCSD)-CEP calculations considering six HLC parameters presented a mean absolute error around 1.15 kcal mol(-1) for all calculated properties. This tendency is intermediate to the G3CEP and G4CEP methods. The use of scaled experimental atomization energies of the elements provided a mean absolute error around 1.11 kcal mol(-1), which is similar to the one obtained by the G4CEP theory (1.09 kcal mol(-1)). The G3X-CEP and G3X(CCSD)-CEP enthalpies of formation were significantly improved with respect to experimental results. Molecular atomization energies showed a modest improvement, while the ionization energies and electronic affinities were slightly affected indirectly by the reoptimized HLC parameters. The proton affinities were nearly unaffected. (AU)

• FAPESP's process: 13/08293-7 - CCES - Center for Computational Engineering and Sciences
• Grantee: Munir Salomao Skaf
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 17/11485-6 - Computational and theoretical developments based on ab initio methods and the Density Functional Theory
• Grantee: Rogério Custodio
• Support Opportunities: Regular Research Grants