Development of electron-proton density functionals for multicomponent density functional theory.

Area of Science:

• Quantum Chemistry
• Computational Physics
• Theoretical Chemistry

Background:

• The Born-Oppenheimer approximation is a cornerstone of molecular simulations, but it limits accuracy for systems with light nuclei.
• Accurate treatment of nuclear quantum effects is crucial for understanding molecular properties, especially for hydrogen.

Purpose of the Study:

• To develop a novel strategy for electron-proton density functionals within multicomponent density functional theory.
• To enable quantum mechanical treatment of selected nuclei alongside electrons, bypassing the Born-Oppenheimer approximation.

Main Methods:

• Development of an electron-proton density functional.
• Utilizing an explicitly correlated electron-proton pair density in the functional derivation.
• Applying multicomponent density functional theory to include nuclear quantum effects.

Main Results:

• The derived electron-proton functional accurately predicts hydrogen nuclear densities.
• This leads to reliable calculations of molecular properties.
• The methodology shows potential for application to larger molecular systems.

Conclusions:

• The proposed strategy offers a robust method for incorporating nuclear quantum effects in electronic structure calculations.
• Accurate hydrogen nuclear densities are achievable, enhancing the predictive power of theoretical chemistry.
• This approach broadens the scope of quantum mechanically treated systems in computational chemistry.