First-Principles Calculation of Jahn-Teller Rotational Distortion Parameters

Area of Science:

• Theoretical and computational chemistry
• Molecular spectroscopy
• Quantum mechanics

Background:

• The Jahn-Teller effect significantly distorts molecular geometry and influences electronic states.
• Accurate determination of parameters like h1 and h2 in the rotational Hamiltonian is crucial for understanding these distortions.
• Existing methods may lack the precision needed for complex Jahn-Teller systems.

Purpose of the Study:

• To develop a robust theoretical and computational framework for molecular Jahn-Teller parameters h1 and h2.
• To provide detailed expressions relating these parameters to molecular properties.
• To validate the framework using experimental data from specific radical molecules.

Main Methods:

• Formulation of a theoretical framework for h1 and h2 parameters.
• Derivation of expressions involving normal coordinates and inertia tensor derivatives.
• Application to cyclopentadienyl, methoxy, and nitrate radicals.
• Comparison with ab initio calculations and first-order perturbation theory.

Main Results:

• The developed framework provides accurate expressions for h1 and h2.
• Calculated h1 and h2 values show good agreement with experimental data for C5H5, CH3O, and NO3 radicals.
• The ab initio parametrization approach outperforms first-order perturbation theory.

Conclusions:

• The new computational method effectively parametrizes h1 and h2 for Jahn-Teller distorted molecules.
• This framework serves as a valuable tool for benchmarking quantum chemistry calculations.
• It facilitates more precise analysis of molecular spectra affected by the Jahn-Teller effect.