Optimized effective potentials to increase the accuracy of approximate proton transfer energy calculations in the excited state

2020 ◽  
Vol 152 (6) ◽  
pp. 064101 ◽  
Author(s):  
Pouya Partovi–Azar ◽  
Daniel Sebastiani
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Transfer Energy ◽  
Energy Calculations ◽  
Effective Potentials

scholarly journals Minimal Optimized Effective Potentials for Density Functional Theory Studies on Excited-State Proton Dissociation

Micromachines ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 679
Author(s):  
Pouya Partovi-Azar ◽  
Daniel Sebastiani
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Proton Transfer ◽  
Density Functional ◽  
Photochemical Reactions ◽  
Transfer Energy ◽  
Functional Theory ◽  
Effective Potentials ◽  
Proton Dissociation ◽  
Dissociation Curves

Recently, a new method [P. Partovi-Azar and D. Sebastiani, J. Chem. Phys. 152, 064101 (2020)] was proposed to increase the efficiency of proton transfer energy calculations in density functional theory by using the T1 state with additional optimized effective potentials instead of calculations at S1. In this work, we focus on proton transfer from six prototypical photoacids to neighboring water molecules and show that the reference proton dissociation curves obtained at S1 states using time-dependent density functional theory can be reproduced with a reasonable accuracy by performing T1 calculations at density functional theory level with only one additional effective potential for the acidic hydrogens. We also find that the extra effective potentials for the acidic hydrogens neither change the nature of the T1 state nor the structural properties of solvent molecules upon transfer from the acids. The presented method is not only beneficial for theoretical studies on excited state proton transfer, but we believe that it would also be useful for studying other excited state photochemical reactions.

scholarly journals Caught in the act: Observation of the solvent response triggered by excited-state proton transfer in real time

2021 ◽  
Author(s):  
Claudius Hoberg ◽  
Thorsten Ockelmann ◽  
James Shee ◽  
Patrick Balzerowski ◽  
Debasish DasMahanta ◽  
...  
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Real Time ◽  
Time Scale ◽  
Stokes Shift ◽  
Transfer Energy ◽  
Optical Pump ◽  
Excited State Proton Transfer ◽  
Electronic Response ◽  
Time Observation

Real-time observation of the solvent response following Excited State Proton Transfer (ESPT) of the photoacid HPTS into water using Optical Pump THz Probe (OPTP) spectroscopy from 0.1 ps up to 300 ps is reported. Subsequent to an instantaneous (< 0.2 ps) electronic response of the solute to photoexcitation, an oscillation with a period of 4 ps involving an intermolecular H (pyranine) - O (water) mode is observed. While for the methylated derivative, MPTS, and the deprotonated photoacid this oscillation relaxes on a time scale of 1.5 – 2 ps, for HPTS the oscillation decays more rapidly within 0.4 ps, which marks the onset of proton transfer. Energy transfer from the excited solute to the solvent takes place on a time scale of 120 ps and is proportional to the Stokes shift associated with energetic relaxation from the Franck-Condon region to the ground state of the photoexcited HPTS.

scholarly journals Pseudo Jahn-Teller Origin of the Proton-transfer Energy Barrier in the Hydrogen-bonded [FHF]-System

2021 ◽  
Author(s):  
Natalia Gorinchoy ◽  
Iolanta Balan ◽  
Victor Polinger ◽  
Isaak Bersuker
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Proton Transfer ◽  
Ab Initio Calculations ◽  
Energy Barrier ◽  
Potential Energy Surfaces ◽  
Vibrational Mode ◽  
Transfer Energy ◽  
Jahn Teller ◽  
Energy Surfaces

The results of ab initio calculations of the adiabatic potential energy surfaces for the proton-bound [FHF]- system at different F-F distances have been rationalized in the framework of the vibronic theory. It is shown that the instability of the symmetric D∞h structure at increased F∙∙∙F distances and the proton displacement to one of the fluorine atoms is due to the pseudo Jahn–Teller mixing of the ground 1Σg electronic state with the lowest excited state of 1Σu symmetry through the asymmetric σu vibrational mode.

scholarly journals An enhanced sampling QM/AMOEBA approach: The case of the excited state intramolecular proton transfer in solvated 3-hydroxyflavone

2021 ◽  
Vol 154 (18) ◽  
pp. 184107
Author(s):  
Michele Nottoli ◽  
Mattia Bondanza ◽  
Filippo Lipparini ◽  
Benedetta Mennucci
Keyword(s):  
Excited State ◽  
Proton Transfer ◽  
Intramolecular Proton Transfer ◽  
Enhanced Sampling
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