Geometries and properties of excited states in the gas phase and in solution: Theory and application of a time-dependent density functional theory polarizable continuum model

Abstract

In this paper we present the theory and implementation of analytic derivatives of time-dependent density functional theory (TDDFT) excited states energies, both in vacuo and including solvent effects by means of the polarizable continuum model. The method is applied to two case studies: p-nitroaniline and 4-(dimethyl)aminobenzonitrile. For both molecules PCM-TDDFT is shown to be successful in supporting the analysis of experimental data with useful insights for a better understanding of photophysical and photochemical pathways in solution.

Formation and relaxation of excited states in solution: A new time dependent polarizable continuum model based on time dependent density functional theory

“…The geometry optimization for the excited state has been performed using the TDDFT energy gradients recently implemented in the development version of the GAUSSIAN package. 19 As already noted the dipole moments of the ground state and of the excited state lie along the C 3 -C 4 bond ͑see Fig. 8 for the numeration of atoms͒, have similar magnitude ͑when computed at the geometry of the ground state they are 2.498 and 3.090 D, respectively͒, but they point towards opposite directions.…”

“…These quantities can be obtained through the extension of the TDDFT approach to analytical energy gradients. 22,23 Very recently 19 this extension has been presented also within the PCM scheme. In this extension the so-called Z-vector 24 ͑or relaxed-density͒ approach is used.…”

“…17,18 In such a generalization, the recent implementation of analytical derivatives of TDDFT excitation energies is used to calculate the change in the one-particle density matrix of the solute due to an electronic transition and the corresponding change in the solvent reaction field. 19 The paper is organized as follows. In Sec.…”

Manganese(II) complexes with thiosemicarbazones as potential anti-Mycobacterium tuberculosis agents

“…Transition energies and oscillator strengths were carried out with time-dependent-DFT (TD-DFT) method [40][41][42][43][44], using M06-2X functional [34]. TD-DFT approach was performed with optimized geometries in the solvent.…”

Computing the Optical Properties of Large Systems

“…This static dielectric constant models the rearrangement of solvent molecules to maximise the screening of the solute molecule, which occurs over a long timescale. The perturbation in the ground state density due to the excitation on the other hand occurs on a very fast timescale, on which the slow degrees of freedom of the solvent cannot react to the change in the electron density of the solute [134]. In this "non-equilibrium regime", the solvent effects are therefore modelled by an effective ∞ dynamic accounting for a screening due to the fast degrees of freedom of the solvent only.…”