Approaching the Hartree-Fock limit by perturbative methods.

Area of Science:

• Computational chemistry
• Quantum chemistry
• Theoretical physics

Background:

• Finite-basis sets in Hartree-Fock calculations introduce errors.
• Approaching the complete-basis limit is crucial for accurate results.
• Existing methods may not sufficiently mitigate basis set incompleteness error.

Purpose of the Study:

• To develop and evaluate novel perturbative methods.
• To improve the accuracy of finite-basis Hartree-Fock (HF) calculations.
• To approach the complete-basis limit efficiently.

Main Methods:

• Development of perturbative correction schemes.
• Application of methods to finite-basis Hartree-Fock (HF) calculations.
• Numerical assessment of error reduction and energy accuracy.

Main Results:

• The proposed perturbative methods demonstrably improve HF calculations.
• Quadratic error reduction was observed with the best performing method.
• Remarkably accurate HF energies were obtained, nearing the complete-basis limit.

Conclusions:

• Perturbative methods offer a viable strategy for enhancing HF calculations.
• Accurate HF energies can be achieved even with finite basis sets.
• These methods advance the precision of quantum chemical computations.