Modern Theoretical Approaches to Modeling the Excited-State Intramolecular Proton Transfer: An Overview

Abstract

The excited-state intramolecular proton transfer (ESIPT) phenomenon is nowadays widely acknowledged to play a crucial role in many photobiological and photochemical processes. It is an extremely fast transformation, often taking place at sub-100 fs timescales. While its experimental characterization can be highly challenging, a rich manifold of theoretical approaches at different levels is nowadays available to support and guide experimental investigations. In this perspective, we summarize the state-of-the-art quantum-chemical methods, as well as molecular- and quantum-dynamics tools successfully applied in ESIPT process studies, focusing on a critical comparison of their specific properties.

Electron-Volt Fluctuation of Defect Levels in Metal Halide Perovskites on a 100 ps Time Scale

“…Additional studies are required to evaluate absorbance of deep defect levels and to select dopants that maximize the absorption while still allowing charges to escape from deep levels by the defect level fluctuation mechanism. The competition between defect-mediated charge recombination and charge escape into bands can be studied by nonadiabatic MD simulation. ,,− …”

Excited-State Intramolecular Proton Transfer in 2-(2′-Hydroxyphenyl)pyrimidines: Synthesis, Optical Properties, and Theoretical Studies

“…Further purification was achieved by crystallization from hexanes. 1 H NMR (CDCl 3 , 500 MHz) δ: 2.56 (s, 6H, 2 × CH 3 ), 6.94 (s, 1H, pyr), 6.94−6.97 (m, 1H, ArH), 7.02 (dd, 1H, J = 8.0 Hz, J = 1.0 Hz, ArH), 7.38 (m, 1H, ArH), 8.54 (dd, 1H, J = 8.0 Hz, J = 1.5 Hz, ArH). 13 C NMR and distortionless enhancement by polarization transfer (DEPT) (CDCl 3 , 125 MHz) δ: 165.9 (C), 164.2 (C), 160.7 (C), 133.0 (CH), 129.2 (CH), 118.9 (CH), 118.6 (C), 117.8 (CH), 117.5 (CH), 23.9 (CH 3 ).…”

“…In the last years, the phenomenon of excited -state intramolecular proton transfer (ESIPT) has been widely studied both from a spectroscopic and theoretical point of view, − since it is a fundamental process in different chemical and biological systems. − Typical ESIPT molecules possess intramolecular hydrogen bonds because the geometric proximity between the proton donor and acceptor units is crucial for ESIPT to occur. ESIPT is usually accompanied by large Stokes shifts, very short lifetimes ( k ≈ 10 13 s –1 ), and often low fluorescence quantum yields in solution.…”

“…Through first-principles calculations, we give an in-depth insight into the ESIPT process and nonradiative deactivation mechanism of this family of compounds. Time-dependent density functional theory (TD-DFT) has shown to be a suitable computational method for a deeper understanding of the ESIPT process, ,− in which the proton transfer takes place in the excited state but not in the ground state.…”

Electron–phonon relaxation at the Au/WSe2 interface is significantly accelerated by a Ti adhesion layer: time-domain ab initio analysis

“…NA-MD is used to model electron-nuclear interactions. [51][52][53][54][55][56][57][58][59] Initially, geometry relaxation, and electronic structure and MD calculations are performed using the Vienna ab initio simulation package (VASP), which uses plane wave basis sets to describe the periodic structure. [60][61][62] The Perdew-Burke-Ernzerhof (PBE) generalized gradient DFT functional described the nonlocal exchange and correlation contribution to the electronic energy.…”