Analysis of the kinetic energy functional in the generalized gradient approximation

Area of Science:

• Quantum Chemistry
• Computational Physics
• Materials Science

Background:

• Accurate calculation of kinetic energy is crucial for electronic structure theory.
• Generalized Gradient Approximation (GGA) methods require improved kinetic energy density functionals.
• Existing functionals struggle with specific limits of the reduced density gradient.

Purpose of the Study:

• Develop a novel density functional for total kinetic energy within the GGA framework.
• Introduce an improved enhancement factor for Pauli kinetic energy density.
• Ensure accurate behavior across different density gradient regimes.

Main Methods:

• Developed a new enhancement factor for total kinetic energy functional.
• Incorporated the conjoint conjecture for interpolation between gradient limits.
• Introduced constraints related to exchange energy functional in the intermediate region.
• Proposed a new enhancement factor for Pauli kinetic energy, enforcing positivity and integral conditions.

Main Results:

• The new functional provides a reasonable description of atomic and molecular kinetic energies with Hartree-Fock densities.
• The proposed Pauli kinetic energy functional exhibits improved behavior at gradient limits.
• The developed methods satisfy necessary physical constraints and limiting behaviors.

Conclusions:

• The novel density functional offers a more accurate approach to calculating total kinetic energy.
• The improvements in kinetic energy density functionals enhance the predictive power of electronic structure calculations.
• This work contributes to the development of more robust computational chemistry and physics tools.