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

Area of Science:

• Computational Chemistry
• Theoretical Chemistry
• Physical Chemistry

Background:

• Excited state proton transfer (ESPT) is crucial in photochemistry.
• Traditional calculations using S1 states can be computationally intensive.
• A recent method proposed using T1 states for enhanced efficiency in ESPT calculations.

Purpose of the Study:

• To evaluate the accuracy of a T1 state-based method for proton transfer energy calculations.
• To assess the efficiency of this method for prototypical photoacids and water systems.
• To investigate the impact of additional effective potentials on T1 state properties and solvent structure.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Time-Dependent DFT (TD-DFT) for reference S1 state calculations.
• T1 state calculations with optimized effective potentials for acidic hydrogens.

Main Results:

• T1 state calculations with one additional effective potential accurately reproduced reference S1 state proton dissociation curves.
• The additional effective potentials did not alter the T1 state's nature.
• Solvent structural properties remained unchanged upon proton transfer.

Conclusions:

• The T1 state method offers a computationally efficient and accurate approach for ESPT energy calculations.
• This method is a valuable tool for theoretical studies of ESPT and other excited-state photochemical reactions.