β Scribed by J. Piskur; L. Borg; A. Stupnik; M. Leisch; W.E. Ernst; B. Holst
No coin nor oath required. For personal study only.
In this paper the correlation between the kinetic energy of helium atoms and the probability of field ionization is investigated by exploiting the narrow velocity distribution of supersonic molecular beams. Field ionization measurements were carried out on supersonic helium beams at 298 K and 95 K corresponding to energies of about 65 meV and 20 meV, respectively, for the individual atoms. The field ionization was performed with a tungsten tip, radius of curvature 12 nm, kept at room temperature. The ionization probability was found to increase by about a factor 10 when the beam was cooled from 298 K to 95 K. The results presented in this paper are of importance for improving the understanding of field ionization and for the development of a new detector for helium and other molecular beams.
π SIMILAR VOLUMES
The direct formation of zero kinetic energy photoelectrons (ZEKE-PE) as well as the formation of PEs by delayed pulsed-field ionization (PFI-PE) has been investigated in photoelectron photoion coincidence (PEPICO) experiments employing synchrotron radiation. Direct ZEKE-PEs and delayed PFI-PEs can e