Jahn-Teller Distortion Driven by Electronic Coherences

The role of electronic coherences in molecular dynamics has recently become a subject of intense investigation given the possibility of measuring their effects using sub-femtosecond laser pulses. Their effect on dynamics occurring at conical intersections has been of been of particular interest. Jahn-Teller (JT) distortion is a canonical example of such non-adiabatic dynamics. We investigate the role of electronic coherences in the JT distortion of Ammonia in its degenerate B ¹E'' state. Using a recently developed formalism and a spectroscopic Hamiltonian we compute the full rovibronic density matrix as a function of time after excitation out of the symmetric ground state. Surprisingly, we find that no population transfer occurs between the JT split electronic states. The JT distortion is driven entirely by coherence between the electronic states.   

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