Practical computation of electronic excitation in solution: vertical excitation model

Abstract

We present a unified treatment of solvatochromic shifts in liquid-phase absorption spectra, and we develop a self-consistent state-specific vertical excitation model (called VEM) for electronic excitation in solution. We discuss several other approaches to calculate vertical excitations in solution as an approximation to VEM. We illustrate these methods by presenting calculations of the solvatochromic shifts of the lowest excited states of several solutes (acetone, acrolein, coumarin 153, indolinedimethine-malononitrile, julolidine-malononitrile, methanal, methylenecyclopropene, and pyridine) in polar and nonpolar solvents (acetonitrile, cyclohexane, dimethyl sulfoxide, methanol, n-hexane, n-pentane, and water) using implicit solvation models combined with configuration interaction based on single excitations and with time-dependent density functional theory

Computational Molecular Electronic Spectroscopy with TD-DFT

“…Despite these limits, TD-DFT clearly remains the most applied theory for evaluating the spectral properties of "real-life" structures and this popularity can be ascribed to the simplicity and speed of use of this singlereference approach and also to the modeling of environmental effects which can be achieved with several theories [26,27]. This general statement is particularly true for solvation effects for which a panel of refined models is now accessible [28][29][30][31][32].…”

Predicting solvatochromic shifts and colours of a solvated organic dye: The example of nile red

“…These fast degrees of freedom are modelled through the relative optical permittivity opt . The contribution to the excitation energy caused through screening by opt can be accounted for in broadly two different ways, the so-called linear-response approach (LR) [40] and the state-specific approach (SS) [41,42]. In the LR approach the solvent polarisation as reaction to the excitation I is dependent on its transition density ρ {1} I , while in the SS approach it is evaluated using the density difference ∆ρ I between the ground state and the excited state.…”

Assessment of a composite CC2/DFT procedure for calculating 0–0 excitation energies of organic molecules

“…In a similar vein, the use of reference data from experimental spectra measured in solution calls for a treatment of solvent effects, which makes it less straightforward to directly assess the intrinsic quality of the quantum chemical description of an excited state. In this regard, gas-phase data are preferable for benchmarking purposes, despite the many methodological possibilities [8][9][10] to model solvatochromic shifts [11][12][13][14].…”