Screened optimally tuned range separated hybrid functional for solvated low bandgap molecular systems

Autor(es)

Dantas Filho, Reinaldo V. ; de Queiroz, Thiago B.

• Tipo de documento: Artigo Científico
• Fonte: Journal of Chemical Physics; v. 161, n. 3, p. 10-pg., 2024-07-21.

Resumo

The description of electronic properties of low bandgap molecular system is often performed by using density functional theory (DFT) and time dependent (TD) DFT calculations with the optimally tuned range-separated hybrid (OT-RSH) functional, as it contains the necessary ingredients to reliably predict charge transfer excitations. However, the range separating parameter (omega) is system-dependent and its optimization, including the chemical environment, is intricate. Refaely-Abramson et al. demonstrated that the gap renormalization in molecular crystals, a ground state property, can be represented by an OT-RSH functional screened by epsilon(static) [Phys. Rev. B 88, 081204(R) (2013)], the zero frequency scalar dielectric constant. In this study, we propose the use of an OT-RSH functional screened by the scalar dielectric constant in the high frequency limit (OT-sRSH), epsilon(infinity), an appropriate constraint for vertical ionization energies or excitations in a dielectric environment. We have performed calculations for S,N-heteroacene derivatives in tetrahydrofuran and dichloromethane. The "unscreened" OT-RSH functional tends to underestimate experimental ionization potentials (IPs) and optical gaps (E(g)s) by up to 1.5 and 0.5 eV, respectively. In contrast, OT-sRSH functional calculations underestimate IPs and E(g)s by only 0.4 and 0.2 eV. We also compared the OT-sRSH results to explicitly solvated OT-RSH functional calculations for oligothiophenes in dioxane, benzene in ammonia, and methylene blue in water. We observe that both the approaches perform similarly for weakly interacting intermolecular systems and deviate for solvent-solute interacting systems, as expected. In conclusion, the OT-sRSH functional can describe molecular systems with environmental polarization effects accurately, a step toward describing realistic molecular systems. (AU)

• Processo FAPESP: 22/03461-8 - Desenvolvimento de aproximações em teoria do funcional da densidade para investigação de processos de separação de cargas
• Beneficiário: Reinaldo Vieira Dantas Filho
• Modalidade de apoio: Bolsas no Brasil - Doutorado Direto
• Processo FAPESP: 20/13466-1 - Design, síntese e caracterização de sistemas moleculares para colheita de luz e separação de cargas
• Beneficiário: Thiago Branquinho de Queiroz
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 24/02191-2 - Descrição de oligômeros de baixo gap óptico e sistemas moléculares doador-aceitador por um funcional híbrido com separação local de alcance
• Beneficiário: Reinaldo Vieira Dantas Filho
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Doutorado Direto