We construct range-separated double-hybrid (RSDH) schemes which combine coupled-cluster or random-phase approximations (RPAs) with a density functional based on a two-parameter Coulomb-attenuating-method-like decomposition of the electron-electron interaction. We find that the addition of a fraction of short-range electron-electron interaction in the wave-function part of the calculation is globally beneficial for the RSDH scheme involving a variant of the RPA with exchange terms. Even though the latter scheme is globally as accurate as the corresponding scheme employing only second-order Møller-Plesset perturbation theory for atomization energies, reaction barrier heights, and weak intermolecular interactions of small molecules, it is more accurate for the more complicated case of the benzene dimer in the stacked configuration. The present RSDH scheme employing a RPA thus represents a new member in the family of double hybrids with minimal empiricism which could be useful for general chemical applications.
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http://dx.doi.org/10.1063/1.5108536 | DOI Listing |
Chemphyschem
November 2024
Department of Chemistry, Cotton University, Guwahati, 781001, India.
Charge Transfer (CT) molecular complexes have recently received much attention in a broad variety of fields. The time-dependent density functional theory (TDDFT), which is essential for studying CT complexes, is a well-established tool to study the excited states of relatively large molecular systems. However, when dealing with donor-acceptor molecules with CT characteristics, TDDFT calculations based on standard functionals can severely underestimate the excitation energies.
View Article and Find Full Text PDFPhys Chem Chem Phys
October 2024
School of Chemistry, The University of Melbourne, Parkville, Australia.
Time-dependent density functional theory (TD-DFT) offers a relatively accurate and inexpensive approach for excited state calculations. However, conventional TD-DFT may suffer from the same poor description of non-covalent interactions (NCIs) which is known from ground-state DFT. In this work we present a comprehensive benchmark study of TD-DFT for excited-state NCIs.
View Article and Find Full Text PDFJ Chem Theory Comput
September 2024
Nantes Université, CNRS, CEISAM UMR 6230, F-44000 Nantes, France.
To expand the QUEST database of highly accurate vertical transition energies, we consider a series of large organic chromogens ubiquitous in dye chemistry, such as anthraquinone, azobenzene, BODIPY, and naphthalimide. We compute, at the CC3 level of theory, the singlet and triplet vertical transition energies associated with the low-lying excited states. This leads to a collection of more than 120 new highly accurate excitation energies.
View Article and Find Full Text PDFJ Chem Theory Comput
June 2024
Department of Chemistry, University at Buffalo State University of New York Buffalo, New York 14260-3000, United States.
Phys Chem Chem Phys
June 2024
Physics and Chemistry of Materials (T-1), Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
Density functional theory (DFT) and electron propagator theory (EPT) calculations were performed to study ground and excited electronic structures of alkali-metal (M) coordinated 9-crown-3, 24-crown-8, [2.1.1]cryptand, -Me-1.
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