State-to-state Scattering of Metastable CO Molecules
from a LiF(100) Surface
Scattering of electronically excited,
state-selected metastable CO(a3Pi)
molecules from a cleaved LiF(100) surface is studied experimentally. Internal
state distributions, fluorescence profiles, Time-Of-Flight (TOF) profiles
and angular distributions of the surviving metastable CO molecules are
measured. Relative and absolute survival probabilities are determined for
various impact velocities. The dependence of translation and rotational
temperature on the velocity of the incoming beam unambiguously indicates
a direct inelastic scattering process, even though the angular distributions
are broad, both in-plane and out-of-plane. The internal state distribution
after scattering shows an overpopulation of the initially prepared Omega=1-component
relative to the other spin-components.
Scattering of Vibrationally and Electronically Excited
CO Molecules from a LiF(100) Surface
Experiments are performed in which vibrationally and electronically excited
CO(a3Pi, v=1) molecules are scattered from a LiF(100) surface. As there
is originally no population in the vibrationless level of the metastable
state, this experiment gives the unique possibility to probe the vibrationally
inelastic channel in the scattering of vibrationally excited molecules.
The vibrational deactivation probability can thus be accurately determined
and is found to be below 10^{-3} for the system under study.
M.C. van Beek, G. Berden, H.L. Bethlem, J.J. ter Meulen.
Molecular Reorientation in Collisions of OH + Ar,
Physical Review Letters 86
(2001) 4001-4004.
