Absence of a guiding effect and charge transfer in the interaction of keV-energy negative ions with Al2O3nanocapillaries

Abstract

In this work, the efficient electron loss process was observed for the transmission of 10- to 18-keV Cu${}^{\ensuremath{-}}$ and Cl${}^{\ensuremath{-}}$ ions through Al${}_{2}$O${}_{3}$ nanocapillaries. The fractions of the scattered particles were simultaneously measured using a position-sensitive microchannel plate detector. The neutrals were guided through the capillary via multiple grazing scattering. In particular, the scattered Cl${}^{\ensuremath{-}}$ ions were observed in the transmission, whereas no Cu${}^{\ensuremath{-}}$ ion was formed. In contrast to highly charged ions, these results support strongly the fact that the scattering events dominate the transport of negative ions through the nanocapillaries and that there is no direct evidence for the formation of negative charge patches inside the capillaries which are able to repulse and guide negative ions efficiently.