Pressure-dependent electronic structure calculations using integral equation-based solvation models.

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Biophysics

Background:

• Accurate prediction of molecular properties in solution under varying pressures is essential for understanding chemical and biological systems.
• Existing computational methods often struggle to capture the complex interplay between electronic and solvation structures at non-ambient pressures.

Purpose of the Study:

• To review and enhance the embedded cluster reference interaction site model (EC-RISM) for calculating pressure-dependent thermodynamic and spectroscopic properties of molecules in water.
• To assess the reliability of the EC-RISM approach for studying pressure-dependent biophysical processes.

Main Methods:

• Utilized self-consistent calculations of electronic and solvation structure using EC-RISM integral equation theory.
• Incorporated pressure effects via solvent response functions and pure solvent density.
• Developed and applied a dispersion-repulsion force field and derived electrostatic interactions from wave functions.

Main Results:

• Successfully predicted pressure-dependent hydration free energies and the autoionization constant of water.
• Accurately reproduced experimental pressure-dependent NMR shifts for trimethylamine N-oxide (TMAO).
• Simulated IR blue-shifts for TMAO and cyanide anion by accounting for solvent relaxation effects.

Conclusions:

• The enhanced EC-RISM method provides a reliable framework for investigating pressure-dependent molecular properties in aqueous solutions.
• This approach is valuable for studying biophysical processes and molecular behavior under varying hydrostatic pressures.