Research
topic:
Collision Induced Processes on Metal Surfaces
Collision Induced Processes (CIP)
involving Trimethylamine ((CH3)3N) ≡ TMA has
been studied on O/Ru(001) using Molecular Beam and TPD techniques. On clean
Ru(001) TMA was found unstable – it dissociates to produce several species
including molecular hydrogen that appears after a multi-step dissociation
process of the parent molecule. After the surface has been partially
passivated by decomposition products TMA adsorption is molecular.
Adsorption on oxygen pretreated surface was found to increase the stability
of TMA. For the first time it was found that TMA reacts with the oxygen
during TPD in a 50% probability to produce CO2 as a major product. Collision with a
hyper-thermal supersonic beam of argon seeded into helium induced a new
process (Collision Induced Rearrangement) in addition to dissociation of
the parent molecule in the second layer (Bi-Layer). The Collision cross
section was calculated (0.25±0.05)Å2. The TMA coverage was not affected during collision with ~1.2eV
argon beams, this indicates that no Collision induced Desorption (CID) took
place. The CIR was found to be thermally irreversible. The threshold energy
for the rearrangement process was measured at ~0.2eV. Collision with argon
ions from the Ion Sputter Gun at ~17eV shows CID of TMA from the surface in
addition to dissociation. Collision Induced Rearrangement was not detected
following collision with argon ions. The collision cross section with argon
ions was 490Å2 – three orders of magnitude larger than
that of collision with the neutral argon beam.