Title: Charge transfer excitations from particle-particle random phase approximation—Opportunities and challenges arising from two-electron deficient systems

Abstract

The particle-particle random phase approximation (pp-RPA) is a promising method for studying charge transfer (CT) excitations. Through a detailed analysis on two-electron deficient systems, we show that the pp-RPA is always able to recover the long-distance asymptotic –1/R trend for CT excitations as a result of the concerted effect between orbital energies and the pp-RPA kernel. We also provide quantitative results for systems with relatively short donor-acceptor distances. With conventional hybrid or range-separated functionals, the pp-RPA performs much better than time-dependent density functional theory (TDDFT), although it still gives underestimated results which are not as good as TDDFT with system-dependent tuned functionals. For pp-RPA, there remain three great challenges in dealing with CT excitations. First, the delocalized frontier orbitals in strongly correlated systems often lead to difficulty with self-consistent field convergence as well as an incorrect picture with about half an electron transferred. Second, the commonly used density functionals often underestimate the energy gap between the highest occupied molecular orbital and the lowest unoccupied molecular orbital (LUMO) for the two-electron deficient species, resulting in systems with delocalized orbitals. Third, the performance of pp-RPA greatly depends on the energy difference between the LUMO and a higher virtual orbital. However, the meaningmore » of the orbital energies for higher virtual orbitals is still not clear. We also discuss the performance of an approximate pp-RPA scheme that uses density functional tight binding (pp-DFTB) as reference and demonstrate that the aforementioned challenges can be overcome by adopting suitable range-separated hybrid functionals. Here, the pp-RPA and pp-DFTB are thus promising general approaches for describing charge transfer excitations.« less

Authors:

Yang, Yang ^[1]; Dominguez, Adriel ^[2]; Zhang, Du ^[1]; Lutsker, Vitalij ^[3]; Niehaus, Thomas A. ^[4]; Frauenheim, Thomas ^[5]; Yang, Weitao ^[6]

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+ Show Author Affiliations

1. Duke Univ., Durham, NC (United States)
2. Max Planck Institute for the Structure and Dynamics of Matter, Hamburg (Germany)
3. Univ. of Regensburg, Regensburg (Germany)
4. Univ. Lyon, Villeurbanne (France)
5. Univ. Bremen, Bremen (Germany)
6. Duke Univ., Durham, NC (United States); South China Normal Univ., Guangzhou (China)

Publication Date:

Wed Mar 22 00:00:00 EDT 2017

Research Org.:

Energy Frontier Research Centers (EFRC), Washington, D.C. (United States). Center for the Computational Design of Functional Layered Materials (CCDM)

Sponsoring Org.:

USDOE Office of Science (SC), Basic Energy Sciences (BES)

OSTI Identifier:

1388076

Grant/Contract Number:  

SC0012575

Resource Type:

Accepted Manuscript

Journal Name:

Journal of Chemical Physics

Additional Journal Information:

Journal Volume: 146; Journal Issue: 12; Related Information: CCDM partners with Temple University (lead); Brookhaven National Laboratory; Drexel University; Duke University; North Carolina State University; Northeastern University; Princeton University; Rice University; University of Pennsylvania; Journal ID: ISSN 0021-9606

Publisher:

American Institute of Physics (AIP)

Country of Publication:

United States

Language:

English

Subject:

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; catalysis (heterogeneous); solar (photovoltaic); energy storage (including batteries and capacitors); hydrogen and fuel cells; defects; mechanical behavior; materials and chemistry by design; synthesis (novel materials)