Vibronically coupled states: computation and characterization of vibronic and rovibronic spectroscopic parameters

Sharma, Ketan

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https://hdl.handle.net/2142/107387 Copy

Description

Title

Vibronically coupled states: computation and characterization of vibronic and rovibronic spectroscopic parameters

Author(s)

Sharma, Ketan

Contributor(s)

• Stanton, John F.
• Miller, Terry A.

Issue Date

2020-06-22

Keyword(s)

Theory and Computation

Abstract

The importance of the breakdown of the Born-Oppenheimer (BO) approximation in the vicinity of a conical intersection has spurred the recent development of computational approches that involve vibronic coupling between electronic states. Computational chemistry has mainly focused on conical intersections along reaction paths. Jahn-Teller type conical intersections offer a spectroscopically accessible alternative that can be used for benchmarking these calculations. The presence of Jahn-Teller and pseudo-Jahn-Teller couplings not only leads to additional terms in the rotational Hamiltonian but also modify how well known terms like Coriolis coupling and spin-rotation coupling are computed. In this talk we build upon the general quantum chemical method pioneered by K\"oppel, Domcke and Cederbaum\footnote{\textsc{H. K\"oppel and W. Domcke and L. S. Cederbaum}~ Multimode Molecular Dynamics Beyond the Born-Oppenheimer Approximation. \textit{Adv. Chem. Phys. 57}, (1984), 59-246} to tackle molecules with vibronic coupling wherein ab initio electronic structure calculations in the adiabatic limit are used as the starting point for calculating properties of molecules in the regime where the BO approximation breaks down. A model vibronic Hamiltonian is parameterized using derivatives of adiabatic potential energy surfaces. Vibronic eigenvectors are obtained from this model Hamiltonian that allow the calculation of parameters in the rotation-spin Hamiltonian that can be determined experimentally from high resolution spectroscopy.

Publisher

International Symposium on Molecular Spectroscopy

Type of Resource

Text

Language

eng

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http://hdl.handle.net/2142/107387

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Copyright 2020 is held by the Author(s)

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