Annealing of CH3I films formed on TTiO2(110) at 90 K has been investigated
using thermal desorption and photodesorption. Ar a surface temperature of 9
0 K, the multilayer film of CH3I grows stochastically. Thermal desorption a
nd photodesorption studies indicate that annealing a CH3I him at temperatur
es of 120-125 K for less than similar to 12 min induces the desorption of w
eakly bound molecules and produces two CH3I phases on TiO2(110): a two-dime
nsional (2D) monolayer phase and a three-dimensional (3D) multilayer phase.
After annealing at similar to 125 K for 12 min, the 3D multilayer phase is
completely desorbed and only the 2D monolayer phase is left on the TiO2(11
0) surface. This 2D layer has a saturation molecular density greater than t
hat of the 1 ML film deposited at 90 K. When the annealing temperature is i
ncreased to above 130 K, the thermal stability of the 2D film increases and
the number of the CH3I molecules left on the TiO2(110) surface decreases.
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