Valence : A Massively Parallel Implementation of the Variational Subspace Valence Bond Method.

Area of Science:

• Computational chemistry
• Quantum chemistry
• Electronic structure theory

Background:

• The variational subspace valence bond (VSVB) method provides an accurate approach for electronic structure calculations.
• Ab initio methods based on nonorthogonal orbitals are crucial for understanding molecular behavior.

Purpose of the Study:

• To introduce the Valence software package for VSVB calculations.
• To highlight the practical features and integration capabilities of the Valence package.

Main Methods:

• Utilizing the ab initio variational subspace valence bond (VSVB) method.
• Employing nonorthogonal orbitals for electronic structure determination.
• Leveraging high parallel scalability for efficient computations.

Main Results:

• The Valence package facilitates automatic wave function construction by combining orbitals.
• It enables modeling of ground and excited states with single configurations.
• Integration with external packages allows for geometry optimization and vibrational frequency calculations.

Conclusions:

• The Valence software package is a valuable, open-source tool for advanced molecular energy calculations.
• Its features promote efficient and flexible use in computational chemistry research.