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SSIMS (FABMS) studies on plasma treated polymers
All3 quantum beats is studied by adsorbing oxygen onto the surface. In addition, we discuss the alignment induced by interactions of a 17 keV H + beam passing through thin carbon foils with and without a deposited layer of lithium. The results presented here demonstrate the sensitivity of these techniques to the influence of overlayers on surface conditions and support the idea that future experiments with detailed surface characterization could provide a basis for theories of the sensitivity of electron pickup to surface electronic structure.
207
Surface Science 211/212 (1989) 207-217 North-Holland, Amsterdam LIFETIMES
OF EXCITED
P. N O R D L A N D E R
ATOMS
NEAR METAL
SURFACES
*
Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA and J.C. T U L L Y
A T&T Bell Laboratories, Murray Hill, NJ 07974, USA Received 21 June 1988; accepted for publication 7 September 1988 We present accurate calculations of the lifetimes and energy shifts of hydrogen and alkali atomic levels near a jellium metal surface. "Complex scaling" of the Schr~Sdinger equation is employed to obtain directly the real and imaginary parts of the atomic resonance energies. Excited atomic levels shift differently with distance and there are many possibilities of level crossings. At such positions the hybridization can be strongly enhanced and lead to states that are oriented towards or away from the surface, with very different lifetimes and non-exponential decay of widths with distance from the surface. Previous calculations of the atomic level widths have not included these facts and typically have overestimated the level widths by several orders of magnitude. We discuss the qualitative consequences of our findings of longer lifetimes and extensive hybridization on the interpretation of neutralization processes in ion-surface collisions. Finally, we show that the presence of a weak lateral corrugation in the surface potential has a similar effect on neutralization as an increased surface temperature.
218
Surface Science 211/212 (1989) 218-226 North-Holland, Amsterdam
SSIMS (FABMS) STUDIES ON PLASMA TREATED POLYMERS E. O C C H I E L L O ,
F. G A R B A S S I
and M. MORRA
Istituto Guido Donegani SpA, 4 Via Fauser, 28100 Novara, Italy Received 18 June 1988; accepted for publication 23 September 1988 The use of SSIMS in evaluating plasma treated polymer surfaces is described. Examples of the obtained information about the site of attack of active species on the polymer surface, crosslinking, loss of aromaticity and functionalization are described. Finally the complementarity of XPS and SSIMS is assessed.
207
Surface Science 211/212 (1989) 207-217 North-Holland, Amsterdam LIFETIMES
OF EXCITED
P. N O R D L A N D E R
ATOMS
NEAR METAL
SURFACES
*
Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37235, USA and J.C. T U L L Y
A T&T Bell Laboratories, Murray Hill, NJ 07974, USA Received 21 June 1988; accepted for publication 7 September 1988 We present accurate calculations of the lifetimes and energy shifts of hydrogen and alkali atomic levels near a jellium metal surface. "Complex scaling" of the Schr~Sdinger equation is employed to obtain directly the real and imaginary parts of the atomic resonance energies. Excited atomic levels shift differently with distance and there are many possibilities of level crossings. At such positions the hybridization can be strongly enhanced and lead to states that are oriented towards or away from the surface, with very different lifetimes and non-exponential decay of widths with distance from the surface. Previous calculations of the atomic level widths have not included these facts and typically have overestimated the level widths by several orders of magnitude. We discuss the qualitative consequences of our findings of longer lifetimes and extensive hybridization on the interpretation of neutralization processes in ion-surface collisions. Finally, we show that the presence of a weak lateral corrugation in the surface potential has a similar effect on neutralization as an increased surface temperature.
218
Surface Science 211/212 (1989) 218-226 North-Holland, Amsterdam
SSIMS (FABMS) STUDIES ON PLASMA TREATED POLYMERS E. O C C H I E L L O ,
F. G A R B A S S I
and M. MORRA
Istituto Guido Donegani SpA, 4 Via Fauser, 28100 Novara, Italy Received 18 June 1988; accepted for publication 23 September 1988 The use of SSIMS in evaluating plasma treated polymer surfaces is described. Examples of the obtained information about the site of attack of active species on the polymer surface, crosslinking, loss of aromaticity and functionalization are described. Finally the complementarity of XPS and SSIMS is assessed.