Adsorption and multilayer growth of thiophene on crystalline and amorphous ice

The adsorption and growth of multilayer films of thiophene on thin ice films deposited on Pt(1 1 1) is studied using reflection–absorption infrared spectroscopy (RAIRS). The multilayer growth of thiophene on Pt(1 1 1) at 125 K is also investigated and serves as reference. A compressed monolayer, a disordered phase, and a crystalline film are subsequently observed in this case. The growth of thiophene films on ice depends on both the structure of the ice and the deposition temperature. A specific adsorption state of thiophene on amorphous ice at 125 K is deduced from the distinct RAIRS in the range between 700 and 900 cm−1. The existence of this state is attributed to a large number of dangling OH groups at this surface. At 85 K this state is not observed. The adsorbed molecules are probably not mobile enough at this temperature to find the specific bonding sites. In the case of crystalline ice the thiophene film growth is somewhat similar to the growth on Pt(1 1 1). In addition, it is found that adsorption of thiophene leads to modifications within the ice layers that again depend on the temperature and the initial structure of the ice.