Assessment of Dressed Time-Dependent Density-Functional Theory for the Low-Lying Valence States of 28 Organic Chromophores

TL;DR

This study evaluates dressed TDDFT's effectiveness in predicting low-lying valence excited states of 28 organic chromophores, highlighting the importance of functional choice and Hartree-Fock exchange inclusion for accurate results.

Contribution

First extensive testing of dressed TDDFT for excitation energies, demonstrating the impact of functional selection and exchange inclusion on accuracy.

Findings

D-TDDFT with Hartree-Fock exchange improves excitation energy predictions.

Choice of functional critically affects positioning of 1h1p and 2h2p states.

Without Hartree-Fock exchange, D-TDDFT increases errors in excitation energies.

Abstract

Almost all time-dependent density-functional theory (TDDFT) calculations of excited states make use of the adiabatic approximation, which implies a frequency-independent exchange-correlation kernel that limits applications to one-hole/one-particle states. To remedy this problem, Maitra et al.[J.Chem.Phys. 120, 5932 (2004)] proposed dressed TDDFT (D-TDDFT), which includes explicit two-hole/two-particle states by adding a frequency-dependent term to adiabatic TDDFT. This paper offers the first extensive test of D-TDDFT, and its ability to represent excitation energies in a general fashion. We present D-TDDFT excited states for 28 chromophores and compare them with the benchmark results of Schreiber et al.[J.Chem.Phys. 128, 134110 (2008).] We find the choice of functional used for the A-TDDFT step to be critical for positioning the 1h1p states with respect to the 2h2p states. We observe that D-TDDFT without HF exchange increases the error in excitations already underestimated by A-TDDFT. This problem is largely remedied by implementation of D- TDDFT including Hartree-Fock exchange.