Quantitative Accuracy in Calculating Charge Transfer State Energies in Solvated Molecular Complexes Using a Screened Range Separated Hybrid Functional within a Polarized Continuum Model

Abstract

A screened-range separated hybrid (SRSH) functional in combination with a polarized continuum model (PCM) was recently implemented within a consistent dielectric polarization treatment. The SRSH-PCM demonstrated excellent agreement of the calculated fundamental orbital gaps with measured energies in the condensed phase. Here we develop a linear response time-dependent DFT (TDDFT) approach to obtain solvated charge transfer state energies. We show that the calculated excited state energies of solvated electron-donor–acceptor complexes are in excellent agreement with measured benchmark values. Specifically we consider donor–acceptor complexes of functionalized anthracenes with tetracyanoethylene in methylene chloride. Our proposed SRSH-PCM calculated energies earn a mean absolute deviation (MAD) from the benchmark values as low as 0.04 eV with optimal tuning in PCM, whereas values based on simpler RSH-PCM, without proper treatment of dielectric screening, are associated with a 0.27 eV MAD.

Efficient Charge Generation via Hole Transfer in Dilute Organic Donor–Fullerene Blends

“…Additional calculations are performed for single molecules and their ions. Condensed phase effects are addressed by the SRSH-PCM framework (16,18). All ground state optimizations and normal mode calculations are carried out employing density functional theory (DFT) at ωB97X-D/6-31G* level (33,34) within the conductor-like polarizable continuum model (PCM) (35).…”

“…All ground state optimizations and normal mode calculations are carried out employing density functional theory (DFT) at ωB97X-D/6-31G* level (33,34) within the conductor-like polarizable continuum model (PCM) (35). Excited state energies and oscillator strengths are obtained by the SRSH-PCM-based TDDFT framework (18) employing PBEh(36) and the 6-31G* basis. Importantly the SRSH-PCM framework achieves a polarization-consistent treatment of the molecular electronic structure affected by the condensed environment represented through the dielectric constant.…”

“…As energy and charge transfer processes strongly depend on the excitation energies, we employ the polarizationconsistent SRSH-PCM framework, which has been shown to yield accurate excitation energies for both excitonic and CT states of condensed phase molecular systems. (16,18). Our analysis considers a DBP-C70 complex in its optimized geometry, assuming that delocalization effects become relevant only on later timescales.…”

Vibronic structure of photosynthetic pigments probed by polarized two-dimensional electronic spectroscopy andab initiocalculations

“…The SRSH-PCM was recently shown to compare well with ionization energies measured in thin-film environments 62. Very recently we used the same protocol to explain the fine spectral splitting of the central pigments in bacterial reaction center64 and to calculate solvated charge-transfer state's energies 63. A related approach, where the α and β tuning was performed without the C-PCM environment, was recently successfully applied to calculate spectral properties 104…”

Synergistic Approach of Ultrafast Spectroscopy and Molecular Simulations in the Characterization of Intramolecular Charge Transfer in Push-Pull Molecules

“…In particular, the energetics of the weakly interacting D-A complexes of pentacene with C60 and poly-3-hexylthiophene (P3HT) calculated within the SRSH-PCM framework, was disclosed to well agree with the experimental energies in the condensed phase [77]. Another example of the SRSH-PCM scheme performance was reported for functionalized anthracenes as electron donors and tetracyanoethylene as acceptor both solvated in methylene chloride, where the calculated excited state energies accurately reproduced the measured benchmark values [79].…”