The photoelectric effect in stereo

Recent advances in attosecond science have enabled access to the detailed dynamics of the most basic interaction between light and matter – Einstein’s photoelectric effect.  Here we show that orientation- and energy-resolved measurements supply another observable, the stereo-Wigner time delay, and that this observable provides precise information on the mean location of the excited electron within the molecule.  Therefore, our work provides the first space- and time-resolved reconstruction of the photoelectric effect, by adding sub-ångstrom spatial- to the existing attosecond temporal-resolution.

We summarize the key points as follows:

• We present, for the first time, a fully orientation- and energy-resolved molecular-frame measurement of the dynamics of ejecting a photoelectron from the diatomic molecule CO, and thereby give a “complete” description of the molecular photoionization dynamics. 
• We produce, for the first time, a significantly large dataset on the photoionization events stemming from a molecule, measured in coincidence with its molecular fragment after ionization so that we can access the spatial structure in the molecular frame.
• We measure and give a new interpretation to a recently introduced observable, namely the stereo Wigner time delay, the time delay difference of ionization events propagating to different sides of the molecule. Specifically, we show that this observable is closely related to the mean position of the electron wave packet at the instant of ionization.
• Our results show that it is possible to extract electron location immediately following ionization purely from experimental measurement alone, without the use of any theoretical models or fitting parameters.

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NCCR MUST highlight:
external pagehttp://www.nccr-must.ch/highlights/vos-keller_2262018.htmlcall_made

Peer reviewed journal publication:
[445] J. Vos, L. Cattaneo, S. Patchkovskii, T. Zimmermann, C. Cirelli, M. Lucchini, A. Kheifets, A. S. Landsman, U. Keller
Download"Orientation-dependent stereo Wigner time delay and electron localization in a small molecule" (PDF, 681 KB)vertical_align_bottom 
Science, vol. 360, Issue 6395, pp. 1326-1330, 2018
Supp. Material: DownloadDownload (PDF, 7.1 MB)vertical_align_bottom 
doi: external page10.1126/science.aao4731call_made

For more journal publications from our group: http://www.ulp.ethz.ch/publications.html