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Exploring the Jahn-Teller and pseudo-Jahn-Teller conical intersections in the ethane radical cation
1School of Chemistry, University of Hyderabad, India.
The Journal of Chemical Physics
|January 6, 2006
Summary
We explored Jahn-Teller (JT) and pseudo-Jahn-Teller (PJT) interactions in ethane radical cations. Dynamic JT effects explain the complex photoionization spectrum, revealing strong pseudo-Jahn-Teller activity.
Area of Science:
- Quantum Chemistry
- Molecular Spectroscopy
- Theoretical Chemistry
Background:
- The ethane radical cation exhibits complex electronic and vibrational structures.
- Jahn-Teller (JT) and pseudo-Jahn-Teller (PJT) effects are crucial for understanding distortions in degenerate electronic states.
Purpose of the Study:
- To theoretically investigate the static and dynamic aspects of JT and PJT interactions in ethane radical cation.
- To correlate theoretical findings with experimental photoionization spectra of ethane.
Main Methods:
- Development of a model diabatic Hamiltonian.
- Ab initio calculations for parameter derivation.
- Analysis of electronic states (2Eg, 2A1g, 2Eu, 2A2u) and vibrational modes (eg symmetry).
Main Results:
- Ethane radical cation ground state has D3d symmetry with a staggered conformation.
- JT distortions are predicted for degenerate electronic states (2Eg) via eg vibrational modes.
- PJT crossings between 2A1g and 2Eg states are energetically favorable.
- Dynamic (E x e)-JT effect explains irregular vibrational progressions in the photoionization spectrum.
- Strong PJT activity in the 2Eg-2A1g manifold causes a diffuse photoelectron band.
Conclusions:
- The study provides a theoretical framework for understanding JT and PJT effects in ethane radical cation.
- Theoretical predictions align with experimental observations of the photoionization spectrum.
- Dynamic JT and PJT interactions significantly influence the electronic and vibrational structure, leading to spectral complexity.
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