Low energy electron interactions with C$\sb2$Cl$\sb4$ and C$\sb6$F$\sb6$ molecules have been studied by using Rydberg atoms. It is observed that the electron attachment process occurs through various channels. Collisions of Rydberg atoms with C$\sb2$Cl$\sb4$ molecules result in the formation of Cl$\sp-$ ions and C$\sb2$Cl$\sb4\sp-$ ions. The data ...

The formation of long-lived ($\tau$ $\gg$ 10 $\mu$sec) product ions through associative ionization reactions of the type: K(nd) + BC $\to$ (KBC)$\sp+$ + e$\sp-$ has been investigated for 8 $\leq$ n $\leq$ 18, using a variety of polyatomic target molecules (denoted BC). Although such reactions clearly involve the Rydberg core ion, the presence of the ...

The design and characterization of an intense source of metastable Ar(3P0,2) atoms is described together with its application in the patterning of Si surfaces. Two different approaches to patterning were investigated. In the first, a hydrogen-passivated Si(100) surface was exposed to the Ar(3P0,2) metastable atom beam, in the presence of a small ...

Potassium Rydberg atoms are used to investigate the lifetimes, on a picosecond timescale, of transient negative ions formed during dissociative electron attachment to CCl$\sb4$ and CF$\sb3$I. The transient negative ions are formed during Rydberg electron transfer reactions of the type$${\rm K}(n{\rm p})+AB\to{\rm K}\sp{+}+AB\sp{-*}\to{\rm ...

Scanning Electron Microscopy with Polarization Analysis (SEMPA) provides a novel tool with which to image surface magnetic structure. In SEMPA, a tightly focussed electron beam is directed at the sample surface and the polarization of the ejected low-energy secondary electrons, which mirrors the local surface magnetization, is measured. A magnetic ...

Localized wavepackets are created in high- n ( n ~ 300) Rydberg atoms which travel in near-circular orbits around the nucleus. Application of carefully tailored electric fields to quasi-1D Rydberg atoms creates coherent superpositions of Stark states with near extreme values of one of the components of the angular momentum. Half-cycle electric field ...

Ion Neutralization Spectroscopy (INS) is a well known probe of surface electronic structure with unparalleled surface specificity. In INS, a beam of singly-charged low-energy rare gas ions is directed at a target surface, and electrons ejected as a result of ion neutralization are analyzed. The use of spin-labeling techniques in INS provides a powerful ...

Development of a low-energy electron-spin-polarized He$\sp+$ ion source is described. The ion source uses an optically pumped rf discharge. Metastable He(2$\sp3$S) atoms are produced by electron impact in the discharge and then are optically pumped into the M$\sb{\rm j}$(M$\sb{\rm s}$) = +1 or $-$1 magnetic sublevels by circularly polarized radiation ...

The characteristics of strongly-polarized quasi-one-dimensional (quasi-1D) Rydberg atoms produced by photoexcitation of selected Stark states in the n = 350 Stark manifold are investigated by studying their ionization when subject to sub-nanosecond unidirectional electric field pulses, termed half-cycle pulses (HCPs), directed both parallel and ...

The present work explores the effect of controlled surface fields on the ionization of Rydberg atoms near surfaces. Lithographically-patterned micrometer scale electrode arrays are used to generate controlled surface electric fields. The data show that application of even small electrode biases (~±1V) can lead to a transition from ionization of the ...