Time-dependent density functional theory approximations for charge separation processes

• Grant number: 22/03461-8
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• Start date: June 01, 2022
• End date: November 30, 2025
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Thiago Branquinho de Queiroz
• Grantee: Reinaldo Vieira Dantas Filho
• Host Institution: Centro de Ciências Naturais e Humanas (CCNH). Universidade Federal do ABC (UFABC). Ministério da Educação (Brasil). Santo André , SP, Brazil
• Associated research grant: 20/13466-1 - Design, synthesis and characterization of molecular systems for light harvesting and charge separation, AP.JP
• Associated scholarship(s): 24/02191-2 - Low bandgap and donor-acceptor molecular systems as described by a hybrid functional with local range separation, BE.EP.DD

Abstract

The mechanisms that lead to efficient charge separation in donor-acceptor molecular systems are not fully established yet. They might be related to electronic states that are above the charge transfer state or boosted by local dielectric screening. Time-Dependent Density Functional Theory (TDDFT) is an excellent tool to investigate these systems, especially when large multimolecular systems need to be explicitly represented, since it has a reasonable computational cost while yet an exact quantum chemistry theory. However, in practice, the exchange-correlation (xc) energy and associated functionals need to be approximated, incorporating conceptual shortages in the theory when describing charge transfer excitations. We aim to develop TDDFT approximations that are appropriated to deal with these transitions in solvated structures and investigate prominent donor-acceptor molecular systems. This will be done by implementing the ``naturally'' screened Optimally Tuned Range Separated Hybrid (OT-RSH) functional in TDDFT applied to covalent and stacked donor-acceptor associations. The systems will be composed by phenothiazine dyes, S,N-heteroacene, and Naphthalene diimide, also in the presence solvent, ionic liquid and other environments proposed in the main project. Furthermore, we aim to collaborate with the group of Prof. Stephan Kummel on implementing Ehrenfest dynamics in their real-time TDDFT code, and evaluate these donor-acceptor systems in order to understand the importance of nuclear motion in charge separation processes. With these strategies we intend to develop TDDFT approximations that can picture the importance of the molecular environment in charge separation and contribute to define its driving mechanisms. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

DANTAS FILHO, REINALDO V.; DE QUEIROZ, THIAGO B.. Screened optimally tuned range separated hybrid functional for solvated low bandgap molecular systems. Journal of Chemical Physics, v. 161, n. 3, p. 10-pg., 2024-07-21. (22/03461-8, 20/13466-1, 24/02191-2)