Homolytic molecular dissociation in natural orbital functional theory

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Molecular Spectroscopy

Background:

• Diatomic molecules are fundamental in chemistry and physics.
• Understanding molecular dissociation is crucial for predicting chemical reactions and material properties.
• Accurate theoretical methods are needed to model electronic structure and dissociation limits.

Purpose of the Study:

• To evaluate the Piris natural orbital functional for describing the dissociation of 14-electron isoelectronic diatomic molecules.
• To compare the Piris functional's performance against the variational two-particle reduced density matrix method and experimental data.
• To analyze the electronic structure and chemical properties of these molecules at their dissociation limits.

Main Methods:

• Application of the Piris natural orbital functional.
• Calculation of dipole moments, natural orbital occupations, and bond orders.
• Analysis of atomic Mulliken populations at the dissociation limit.
• Comparison with CASSCF results and experimental data.

Main Results:

• The Piris functional correctly predicts integer electron counts at dissociation, unlike methods using D, Q, G conditions.
• Calculated chemical properties align well with accurate CASSCF and experimental values.
• The study provides insights into the electronic structure and bonding of the studied isoelectronic series.

Conclusions:

• The Piris natural orbital functional is a reliable method for studying diatomic molecule dissociation.
• This functional offers an accurate and N-representable approach to electronic structure calculations.
• The findings support the use of the Piris functional for future theoretical chemistry research.