Constrained Nuclear-Electronic Orbital Density Functional Theory with a Dielectric Continuum Solvent Model.

Area of Science:

• Computational Chemistry
• Theoretical Chemistry
• Physical Chemistry

Background:

• Solvent effects are essential for accurate simulations of chemical and biological systems in solution.
• Continuum solvation models are common for including solvent effects.
• Nuclear quantum effects (NQEs) are significant for hydrogen-containing systems.

Purpose of the Study:

• To develop a computational method that simultaneously accounts for both nuclear quantum effects and solvent effects.
• To apply this method to understand anomalous experimental observations in solution.

Main Methods:

• Coupling constrained nuclear-electronic orbital density functional theory (cNEO-DFT) with a dielectric continuum solvation model.
• Simulating the formate ion to investigate C-H stretch frequency and solvatochromic shifts.

Main Results:

• The new method accurately captures both NQEs and solvent effects.
• The vibrational frequency of the C-H stretch in the formate ion was accurately reproduced.
• The anomalous solvatochromic shift observed experimentally was explained.

Conclusions:

• The combined approach provides a more reliable way to simulate chemical processes in solution.
• This method is crucial for systems where both NQEs and solvent interactions are important.
• Accurate prediction of spectroscopic properties like solvatochromic shifts is achievable.