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Calculations of the lowest valence {\pi}* as well as the 3s and higher energy 3p{\sigma} Rydberg excited states of the CO2 molecule are carried out using density functionals with variational optimization of the orbitals, an approach…

Chemical Physics · Physics 2026-04-08 Darío Barreiro-Lage , Gianluca Levi , Hannes Jonssón , Thanja Lamberts

A direct orbital optimization method is presented for density functional calculations of excited electronic states using either a real space grid or a plane wave basis set. The method is variational, provides atomic forces in the excited…

Computational Physics · Physics 2022-11-09 Aleksei V. Ivanov , Gianluca Levi , Elvar Ö. Jónsson , Hannes Jónsson

Rydberg excited states of molecules pose a challenge for electronic structure calculations because of their highly diffuse electron distribution. Even large and elaborate atomic basis sets tend to underrepresent the long-range tail, overly…

Excited electronic states of molecules and solids play a fundamental role in fields such as catalysis and electronics. In electronic structure calculations, excited states typically correspond to saddle points on the surface described by…

The performance of time-independent, orbital optimized calculations of excited states is assessed with respect to charge transfer excitations in organic molecules in comparison to the linear-response time-dependent density functional theory…

Chemical Physics · Physics 2024-05-22 Elli Selenius , Alec Elías Sigurdarson , Yorick L. A. Schmerwitz , Gianluca Levi

The ground state of atoms from H to Ar was calculated using a self-interaction correction to local and gradient dependent density functionals. The correction can significantly improve the total energy and makes the orbital energies…

Atomic and Molecular Clusters · Physics 2013-08-29 Simon Klüpfel , Peter Klüpfel , Hannes Jonsson

We present a new nonempirical density functional generalized gradient approximation (GGA) that gives significant improvements for lattice constants, crystal structures, and metal surface energies over the most popular Perdew-Burke-Ernzerhof…

Materials Science · Physics 2009-11-11 Zhigang Wu , Ronald E. Cohen

We present an approach for accurate calculation of exchange energy and total energy for excited states using time independent density functional formalism. This is done by inclusion of gradient correction into the excited state exchange…

Chemical Physics · Physics 2012-01-31 Md. Shamim , Manoj K. Harbola

Variational calculations of excited electronic states are carried out by finding saddle points on the surface that describes how the energy of the system varies as a function of the electronic degrees of freedom. This approach has several…

Chemical Physics · Physics 2023-02-15 Yorick L. A. Schmerwitz , Gianluca Levi , Hannes Jónsson

Self-consistent calculations using the Perdew-Zunger self-interaction correction (PZ-SIC) to local density and gradient dependent energy functionals are presented for the binding energy and equilibrium geometry of small molecules as well as…

Atomic and Molecular Clusters · Physics 2013-08-30 Simon Klüpfel , Peter Klüpfel , Hannes Jónsson

Configuration-interaction-type calculations on electronic and vibrational structure are often the method of choice for the reliable approximation of many-particle wave functions and energies. The exponential scaling, however, limits their…

Computational Physics · Physics 2019-05-24 Alberto Baiardi , Christopher J. Stein , Vincenzo Barone , Markus Reiher

Density functional theory (DFT) is a widespread and effective tool in electronic structure calculations for ground-state electron systems. Its success has prompted exploration into the use of DFT for non-collective excited states. The delta…

Chemical Physics · Physics 2025-08-12 Ethan Pollack , Rohan Maniar , John P. Perdew

Orbital-optimized density functional theory (DFT) has emerged as an alternative to time-dependent (TD) DFT capable of describing difficult excited states with significant electron density redistribution, such as charge-transfer, Rydberg,…

Chemical Physics · Physics 2025-01-22 Hanh D. M. Pham , Rustam Z. Khaliullin

It is known that the adiabatic approximation in time-dependent density functional theory usually provides a good description of low-lying excitations of molecules. In the present work, the capability of the adiabatic nonempirical…

Materials Science · Physics 2009-11-13 Jianmin Tao , Sergei Tretiak , Jian-Xin Zhu

We present a general approach to converge excited state solutions to any quantum chemistry orbital optimization process, without the risk of variational collapse. The resulting Square Gradient Minimization (SGM) approach only requires…

Chemical Physics · Physics 2020-03-11 Diptarka Hait , Martin Head-Gordon

Sun et al. [J. Chem. Phys. 144, 191101 (2016)] suggested that common density functional approximations (DFAs) should exhibit large energy errors for excited states as a necessary consequence of orbital nodality. Motivated by…

Computational Physics · Physics 2022-11-09 Sebastian Schwalbe , Kai Trepte , Susi Lehtola

Density functional theory (DFT) based modeling of electronic excited states is of importance for investigation of the photophysical/photochemical properties and spectroscopic characterization of large systems. The widely used linear…

Chemical Physics · Physics 2021-05-11 Diptarka Hait , Martin Head-Gordon

Successful modern generalized gradient approximations (GGA's) are biased toward atomic energies. Restoration of the first-principles gradient expansion for exchange over a wide range of density gradients eliminates this bias. We introduce…

It has been argued that precise measurements of optical transition frequencies between Rydberg states of hydrogen-like ions could be used to obtain an improved value of the Rydberg constant and even to test Quantum Electrodynamics (QED)…

General Relativity and Quantum Cosmology · Physics 2018-08-01 F. Dahia , E. Maciel , A. S. Lemos

Standard spin-density functionals for the exchange-correlation energy of a many-electron ground state make serious self-interaction errors which can be corrected by the Perdew-Zunger self-interaction correction (SIC). We propose a…

Materials Science · Physics 2014-01-28 Mark R Pederson , Adrienn Ruzsinszky , John P. Perdew
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