Issue
EPL
Volume 77, Number 3, February 2007
Article Number 33002
Number of page(s) 6
Section Atomic, Molecular and Optical Physics
DOI http://dx.doi.org/10.1209/0295-5075/77/33002
Published online 01 February 2007
EPL, 77 (2007) 33002
DOI: 10.1209/0295-5075/77/33002

Chemical sputtering by impact of excited molecules

P. S. Krstic1, C. O. Reinhold1 and S. J. Stuart2

1  Physics Division, Oak Ridge National Laboratory - P.O. Box 2008, Oak Ridge, TN 37831-6372, USA
2  Department of Chemistry, Clemson University - Clemson, SC 29634, USA

krsticp@ornl.gov

received 17 August 2006; accepted in final form 6 December 2006; published February 2007
published online 1 February 2007

Abstract
We study chemical sputtering of deuterated amorphous carbon surfaces by ${\rm D}$ atoms, vibrationally excited ${\rm D}_{2}$, and dissociating ${\rm D}_{3}$ molecules, in a range of impact energies, $7.5\hbox{--} 30\,{\rm eV}/{\rm D}$. We analyze the role of the internal state, i.e. the vibrationally excited and dissociating states of the neutral molecules resulting from above-surface neutralization of impacting molecular ions in typical sputtering experiments. The sputtering yields are shown to considerably increase with the internal vibrational energy at the lowest impact energies. By comparison of calculated and measured yields we draw conclusions regarding the possible mechanisms for neutralization.

PACS
34.50.Dy - Interaction of atoms and molecules with surfaces; photon and electron emission; neutralization of ions.
52.40.Hf - Plasma-material interactions; boundary layer effects.
68.03.Hj - Structure: measurements and simulations.

© Europhysics Letters Association 2007