Here it is shown how ultrafast nonradiative decay pathways in organic chromophores may be i) discovered using ab initio quantum dynamics approaches, and ii) potentially imaged using time-resolved core-spectroscopies. In particular, the 'on-the-fly' determination of the requisite potential energy surfaces using high-level quantum chemistry methods is demonstrated to be a useful approach for uncovering the character of the large amplitude nuclear motion that engenders fast relaxation to the ground state via conical intersections. Furthermore, the direct simulation of time-resolved observables arising from X-ray absorption (eg. XAS, XPS) that would probe these processes on the inherent femtosecond timescales of vibrational motion will be discussed. It will be shown that these core spectroscopies are incredibly sensitive to the degrees of freedom of interest: the electronic and nuclear character of the wave packet, and specifically, in regions near conical intersections. Given the complexity of the resultant spectral signatures of the molecular dynamics, high level simulation is shown to be an invaluable component in the interpretation of the experimental results.

Signatures of nonadiabatic dynamics from time-resolved X-ray spectroscopies

256th National Meeting (2018)

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