Desorption of cluster ions from solid Ne by low-energy ion impact

Abstract

Abstract. We investigated Ne+ ions and Ne + n (n = 2 − 20) cluster ions desorbed from the surface of solid Ne by 1.0 keV Ar + ion impact. Kinetic energy analysis shows a considerably narrower energy distribution for the Ne + n (n ≥ 3) ions than for the Ne + n (n = 1, 2) ions. The dependence of ion yields on Ne film thickness indicates that cluster ions (n ≥ 3) are desorbed only from relatively thick films. We conclude that desorbed ions grow into large cluster ions during the outflow of deep bulk atoms to the vacuum.

Temperature effects on ion-desorption dynamics from solid Ne by low-energy ion impacts

“…This charge-up phenomenon is mostly caused by emission of secondary electrons generated by the ion impacts. In fact, the desorption energy is known to be below 2 eV, as measured for 120 MLs solid Ne, for which no charge-up effect is expected [14]. The kinetic energy of Ar + 2 photodesorbed from solid Ar was reported to be less than 1 eV [15].…”

“…The kinetic energies of Ne + n (n = 1 − 3) decrease with size, while those of Ne + n (n ≥ 4) ions are largely independent of size. A detailed discussion of the process of Ne-cluster-ion formation and the dependence of kinetic energy on cluster size is given elsewhere [14].…”

Temperature effect of metastable atom desorption from solid Ne by low-energy electron impact

“…We will discuss the results within the framework of the CE mechanism, and we also performed a simple trajectory calculation of desorbed excited Ne atoms. Figure 1 shows a side view of the experimental setup, which was similar to the one we used in our previous work [3][4][5], except for the addition of a low-energy electron gun and a channel electron multiplier (CEM) for the detection of desorbed metastable atoms. The main chamber was evacuated by a series of turbo molecular pumps and a Ti-getter pump, resulting in a pressure of approximately 3·10 -8 Pa.…”