Time-of-flight studies of high Rydberg states in atomic lithium excited by electron impact

Carl A. Kocher, A.J. Smith

G. D. Stevens, M. T. Widmer, F. Tudorica +2 more

Carl A. Kocher, A.J. Smith

Lithium atoms in high Rydberg states, excited in an atomic beam by pulsed electron impact, are passed through a target gas and detected following electric-field state selection. Cross sections obtained from time-of-flight spectra are virtually independent of the principal quantum number and in numerical agreement with calculations for deflection of the core ion alone. This deflection has also been observed directly. These results suggest a new method for very-low-energy ion-atom scattering experiments.

M. Kent Ballard

C.L. Shepard

Carl A. Kocher, C.L. Shepard

The distribution of principal quantum numbers for high-Rydberg states of lithium, produced in a thermal atomic beam by electron impact excitation, has been determined after passage of the beam through gaseous targets. Target densities were selected for an approximately tenfold reduction of the on-axis flux of Rydberg atoms. The state distribution, determined by electric field ionization, is markedly affected by a target of rapidly rotating polar molecules having rotational energy level separations comparable to the binding energy of the Rydberg valence electron. However, the distribution is not appreciably influenced by rare-gas or slowly rotating polar molecular targets, for which the Rydberg beam spreads as a result of momentum transfer.