Jm. Goodkind et Gf. Saville, THE INFLUENCE OF IONS AND RADIATION ON TUNNELING OF ELECTRONS FROM THE SURFACE OF LIQUID-HELIUM, Zeitschrift fur Physik. B, Condensed matter, 98(3), 1995, pp. 315-318
In work previously reported by Saville et al. [1] and Saville [2], we
found that electrons tunneling from their shallow potential well above
the surface of liquid helium behave as an almost ideal 1D hydrogen at
om. Computations [3], without approximation or adjustable parameters,
using the time dependent Schrodinger equation are in excellent agreeme
nt with measured tunneling rates. The same computation method was used
to compute the influence of AC fields on the tunneling rates [3] as p
reparation for planned experiments. In this paper I discuss phenomena
which appear to set upper and lower limits on the observable tunneling
rates. Lower limits were determined by photo assisted escape due to t
hermal radiation and by cosmic ray generation of ions in the bulk liqu
id helium. Upper limits were set by the creation of excitations in the
superfluid film on the top of the sample chamber when electrons impac
ted with energy greater than 21.6 eV. Through its influence on the tun
neling rate, we were also able to measure very small changes in the el
ectron potential at the surface due to a sub-monolayer coverage of He-
3.