Mainz 2017 – wissenschaftliches Programm

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A: Fachverband Atomphysik

A 3: XUV/X-ray spectroscopy I

A 3.1: Hauptvortrag

Montag, 6. März 2017, 14:30–15:00, N 2

Excited state molecular dynamics: new insights from x-ray spectroscopy and scattering — •Markus Gühr — Institut für Physik und Astronomie, Universität Potsdam

The conversion of light energy into other energetic forms is accomplished via electronically excited states. Visible and ultraviolet light initially deposits energy in the molecular electronic degrees of freedom. The coupling between electronic and nuclear degrees of freedom on an ultrafast timescale determines the efficiency and selectivity of energy conversion into heat, chemical transformation or charge transfer. Understanding of the energy conversion processes therefore requires information on electronic and nuclear molecular degrees of freedom.
Time resolved spectroscopy using femtosecond x-ray pulses provides a new window into the molecular excited states dynamics. Due to the x-ray typical element and site selectivity, the method provides highly local information on nonadiabatic dynamics. I will discuss the progress in this field and present new experiments on the excited state decay from a π state to an n state, probed at the oxygen K-edge [1].
In addition, I will present recent approaches to directly image molecular dynamics using x-rays and relativistic electron pulses. For the latter I will show how electrons can be used to directly image vibrational wavepackets in an isolated molecule [2].
T. Wolf, R Heilemann Myhre et al., arXiv:1610.08498 (2016)
Yang, J., Guehr et al., Phys. Rev. Lett. 117, 173002 (2016)