Erlangen 2018 – scientific programme
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MO: Fachverband Molekülphysik
MO 22: Posters 3: Experimental and Theoretical Techniques and High Resolution Spectroscopy
MO 22.10: Poster
Thursday, March 8, 2018, 16:15–18:15, Zelt West
Low-energy electron emission in strong-field photoionization of methane — •Martin Laux, Nicolas Camus, Yonghao Mi, Lutz Fechner, Robert Moshammer, and Thomas Pfeifer — Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
We present results of strong-field ionization of methane measured in a Reaction Microscope (Remi) by 25 fs, 800/400 nm two-color laser pulses. Photoelectron spectra were analyzed separately for different ionization and dissociation channels, which could be identified by the ion fragments detected in coincidence, i.e. CH4+, CH3+, and H+. The spectra differ significantly from each other at kinetic energies below 0.5 eV, in contradiction to the established two-step model of molecular photoionization [1]. However, autoionization of vibrationally excited Rydberg states is found to explain the enhancement of low-energy electrons. Our findings generalize this strong-field excitation and autoionization mechanism, observed recently in molecular hydrogen [2], to more complex systems.
M.F. Kling et al., Science 312, 246 (2006)
Y. Mi et al., Phys. Rev. Lett. 118, 183201 (2017)