Growth and orientation of naphthalene films on Ag(111)

The growth of naphthalene films on Ag(111) was studied by reflection absorption infrared spectroscopy (RAIRS) and temperature-programmed desorption (TPD). The molecular orientation of naphthalene was also calculated using the surface infrared spectroscopy selection rule. Naphthalene adsorption at 210 K is limited to a monolayer. During dosing at 150 K, naphthalene forms a metastable second layer prior to multilayer formation. TPD results suggest that the metastable second layer desorbs at a temperature about 9 K lower than the multilayer and that the second layer rearranges to become part of the multilayer as the latter forms. RAIRS results indicate that naphthalene rings in the monolayer lie parallel to the surface, whereas in the metastable layer these rings are tilted away from the Surface plane.