Adsorption desorption of carbon suboxide (C3O2) on amorphous and crystalline ice films monitored by infrared spectroscopy

The carbon suboxide (C3O2) interactions with amorphous or crystalline ice s urfaces in high vacuum are studied using temperature-programmed desorption (TPD) monitored by Fourier transform infrared spectroscopy (FTIR). We show clearly that unlike with crystalline film, in the 125-145 K temperature ran ge, the adsorbate-covered amorphous ice surface presents a near monolayer s tate in which the C3O2 forms a hydrogen bond with the free OH groups of the ice surface. The C3O2 desorption from amorphous ice film seems to be induc ed by the onset of the crystallization of the amorphous ice into the cubic state. The activation energy for desorption is evaluated from a first-order regime to be 43 +/- 2 kJ mol(-1) and is consistent with the existence of a hydrogen-bonded adsorbed state.