Multispectral time-resolved energy-momentum microscopy using high-harmonic extreme ultraviolet radiation.

A 790-nm-driven high-harmonic generation source with a repetition rate of 6 kHz is combined with a toroidal-grating monochromator and a high-detection-efficiency photoelectron time-of-flight momentum microscope to enable time- and momentum-resolved photoemission spectroscopy over a spectral range of 23.6-45.5 eV with sub-100 fs time resolution.

The photoelectron angular distribution of water clusters.

The angular distribution of photoelectrons emitted from water clusters has been measured by linearly polarized synchrotron radiation of 40 and 60 eV photon energy. Results are given for the three outermost valence orbitals. The emission patterns are found more isotropic than for isolated molecules.

Autoionization mediated by electron transfer.

Electron-electron coincidence spectra of Ar-Kr clusters after photoionization have been measured. An electron with the kinetic energy range from 0 to approximately 1 eV is found in coincidence with the Ar 3s cluster photoelectron. The low kinetic energy electron can be attributed to an Ar + Kr+ + Kr+ final state which forms after electron transfer mediated decay.

Interatomic Coulombic decay in mixed NeKr clusters.

We report the occurrence of interatomic Coulombic decay (ICD) in mixed NeKr clusters. A well-defined feature ranging from 9 to 12 eV in kinetic energy is observed in coincidence with the Ne 2s photoelectrons. It derives from an ICD process, in which an initial Ne 2s vacancy is filled by a Ne 2p electron and an electron is emitted from a 4p level on a neighboring Kr atom.