Desorption induced by atomic and molecular ion collisions on LiF

Journal Article · Thu Jun 10 04:00:00 EDT 1999 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.59269· OSTI ID:21208012

Pereira, J A. M.; Silveira, E F. da ^[1]

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1. Depto. de Fisica, Lab. Van de Graaff, PUC-Rio, CP 38071, 22952-970 Rio de Janeiro (Brazil)

Atomic and molecular nitrogen ion beams, produced by the PUC-Rio Van de Graaff accelerator, were used to bombard lithium fluoride thin films. Desorption of secondary ions was measured by means of a time-of-flight mass spectrometer equipped with a double grid acceleration system. The outputs of the experiment are the axial kinetic energy distribution and the desorption yield of the emitted ions. This information allowed determination of the relative contribution to desorption due to collision cascades (nuclear sputtering) and to electronic excitation (electronic sputtering). It was observed that F{sup -} ions are desorbed as a result of collision cascades and that the F{sup -} ion yields depends linearly on the number of constuents in the projectile, i.e., Y(N{sub 2}{sup +})=2Y(N{sup +}). The emission of clusters such as (LiF)Li{sup +} was found to be caused by electronic excitation and the (LiF)Li{sup +} yield revealed a nonlinear dependence: Y(N{sub 2}{sup +})>2Y(N{sup +}). Both processes were found to contribute to Li{sup +} desorption. These effects are discussed in terms of the density of deposited energy which depends on the projectile velocity and on the electronic stopping power.

• OSTI ID: 21208012
• Journal Information: AIP Conference Proceedings, Journal Name: AIP Conference Proceedings Journal Issue: 1 Vol. 475; ISSN APCPCS; ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
DESORPTION
EXCITATION
FLUORINE IONS
ION BEAMS
ION COLLISIONS
ION EMISSION
LITHIUM FLUORIDES
LITHIUM IONS
MASS SPECTRA
MOLECULAR IONS
NITROGEN IONS
NONLINEAR PROBLEMS
STOPPING POWER
THIN FILMS
TIME-OF-FLIGHT METHOD
VAN DE GRAAFF ACCELERATORS
YIELDS