Approximating Quasiparticle and Excitation Energies from Ground State Generalized Kohn-Sham Calculations

Abstract

Quasiparticle energies and fundamental band gaps in particular are critical properties of molecules and materials. It was rigorously established that the generalized Kohn-Sham HOMO and LUMO orbital energies are the chemical potentials of electron removal and addition and thus good approximations to band edges and fundamental gaps from a density functional approximation (DFA) with minimal delocalization error. For other quasiparticle energies, their connection to the generalized Kohn-Sham orbital energies has not been established but remains highly interesting. We provide the comparison of experimental quasiparticle energies for many finite systems with calculations from the GW Green's function and localized orbitals scaling correction (LOSC), a recently developed correction to semilocal DFAs, which has minimal delocalization error. Extensive results with over forty systems clearly show that LOSC orbital energies achieve slightly better accuracy than the GW calculations with little dependence on the semilocal DFA, supporting the use of LOSC DFA orbital energies to predict quasiparticle energies. This also leads to the calculations of excitation energies of the $N$-electron systems from the ground state DFA calculations of the $\left(N-1\right)$-electron systems. Results show good performance with accuracy similar to TDDFT and the delta SCF approach for valence excitations with commonly used DFAs with or without LOSC. For Rydberg states, good accuracy was obtained only with the use of LOSC DFA. This work highlights the pathway to quasiparticle and excitation energies from ground density functional calculations.

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Cited by in corpus (8)

• Charge Transfer Excitation Energies From Ground State Density Functional Theory Calculations
• Combining Localized Orbital Scaling Correction and Bethe-Salpeter Equation for Accurate Excitation Energies
• Machine learning optimization of the collocation point set for solving the Kohn-Sham equation
• Renormalized Singles with Correlation in $GW$ Green's Function Theory for Accurate Quasiparticle Energies
• Correcting Delocalization Error in Materials with Localized Orbitals and Linear-Response Screening
• The Exact Second Order Corrections and Accurate Quasiparticle Energy Calculations in Density Functional Theory
• Eliminating Delocalization Error through Localized Orbital Scaling Correction with Orbital Relaxation from Linear Response
• Self-consistent calculation of localized orbital scaling correction for correct electron densities and energy level alignment in density functional theory