Fig. 1: Overview of dissociative and non-dissociative ionization of methane and its measurement by attosecond electron-ion-coincidence spectroscopy.
From: Attosecond delays between dissociative and non-dissociative ionization of polyatomic molecules
a Sketch of the potential-energy surfaces of methane cation in the Franck-Condon region. The JTE causes the appearance of a three-fold conical intersection and a broad photoelectron band (taken from ref. 36) associated with HOMO ionization. b One-dimensional cut through the potential-energy surfaces along the C-H bond-dissociation coordinates obtained from CASSCF/MRCI calculations by relaxing all other nuclear-geometry parameters. c Schematic diagram of the attosecond coincidence interferometer. The phase-locked XUV-APT pump and NIR probe pulse serve as an attosecond clock to monitor the ultrafast electron dynamics at the instant of photoionization. d Measured photoelectron spectra following photoionization with an XUV-APT generated in xenon and containing harmonic orders 11, 13, and 15. e Energy sharing between photoion and photoelectron is represented in terms of their respective kinetic energies Ee and Emol.
