The performance of exchange-correlation functionals in describing electron density parameters of saddle point structures along chemical reactions

Author(s)

Macedo, Gabriel Kossaka ; Andrade Haiduke, Roberto Luiz

• Document type: Journal article
• Source: Journal of Computational Chemistry; v. 43, n. 27, p. 9-pg., 2022-09-02.

Abstract

This work is focused on evaluating the performance of exchange-correlation functionals from density functional theory in providing descriptor values derived from the electron density of saddle point structures (transition states) in chemical reactions. The properties investigated were obtained from the quantum theory of atoms in molecules, including atomic charges and electron density topological data at the bond critical points. In addition, parameters from the Interacting quantum atom energy partition were used as well in this comparative study. The reference values are attained in coupled cluster calculations with iterative single and double excitations (CCSD). Six elementary reactions are considered here: CO + H-2 <-> H2CO, CO + H2O <-> HCOOH, HCN <-> HNC, H + F-2 <-> HF + F, H + N-2 <-> HN2, and H + CO <-> HCO. In general, the BB1K functional (hybrid-meta-generalized gradient approximation) provides the best description of these properties. Our study indicates that an intermediate percentage of nonlocal exact exchange, around 40%-55% (perhaps even larger), is probably required for attaining more accurate values with actual functionals, although this condition is not able of explaining all the trends observed. (AU)

• FAPESP's process: 14/23714-1 - Electronic structure relativistic calculations for evaluation of new prolapse-free basis sets
• Grantee: Roberto Luiz Andrade Haiduke
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/12675-6 - Stability analysis of transition states in chemical reactions by means of tools from the quantum theory of atoms in molecules
• Grantee: Gabriel Kossaka Macedo
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)