SEST: Simulated Electronic Structure Theory.

Area of Science:

• Computational Chemistry
• Theoretical Chemistry
• Quantum Chemistry

Background:

• Accurate modeling of molecular electronic structure is crucial for understanding chemical properties and reactions.
• Existing methods often require significant computational resources.
• Developing efficient and accurate empirical models remains an active area of research.

Purpose of the Study:

• To introduce a novel empirical approach for modeling molecular electronic structure.
• To establish relationships between molecular orbital energy components and interatomic distances.
• To validate the new theory using small molecules.

Main Methods:

• Developed a theory based on relationships between molecular orbital energy components and average electron-electron/electron-nucleus distances.
• Related these distances to interatomic distances for empirical modeling.
• Defined a general energy expression and interatomic distance-dependent energy functions.
• Applied the theory to model the hydrogen molecule, first-row hydrides, and ethane.

Main Results:

• The developed models accurately reproduced RHF/6-31G(d) optimized geometries.
• Models successfully fitted RHF/6-31G(d) energies at equilibrium.
• Models also fit UHF/6-31G(d) energies at the bond dissociation limit.
• Simulated vibrational frequencies were consistent with theoretical calculations.

Conclusions:

• The novel empirical approach provides a viable method for modeling molecular electronic structure.
• The theory demonstrates accuracy in predicting key molecular properties like geometry, energy, and vibrational frequencies.
• This method offers a potentially more efficient alternative for electronic structure calculations.