Conceptual density functional theory under pressure: Part I. XP-PCM method applied to atoms

Area of Science:

• Physical Chemistry
• Quantum Chemistry
• Materials Science

Background:

• High pressure chemistry traditionally focuses on thermodynamics and volume changes.
• Electronic effects at the molecular scale under extreme pressure remain underexplored.

Purpose of the Study:

• To integrate conceptual Density Functional Theory (DFT) with pressure simulation methods.
• To investigate the electronic and reactivity changes of atoms under high pressure (GPa range).

Main Methods:

• Utilized the conceptual DFT framework combined with the XP-PCM method for pressure simulations.
• Derived electronic atomic volume and compressibility from energy derivatives with respect to pressure.
• Analyzed changes in ionization potential, electron affinity, electronegativity, and chemical hardness.

Main Results:

• Electronic atomic radii and compressibility were quantified and correlated with known values.
• Ionization potential and electron affinity decrease with pressure; electronegativity decreases, while hardness increases.
• Atomic electron density concentrates inwards, exhibiting periodic trends analyzed via quantum similarity indices.

Conclusions:

• The extended DFT framework successfully reveals electronic atomic properties and reactivity under high pressure.
• Clear periodic patterns in atomic properties and electron density distribution emerge under pressure.
• This approach offers new insights into materials science and chemical reactivity control via pressure.