Preliminary study of the influence of environment conditions on the successive hydrogenations of CO.

The successive hydrogenation of CO has been investigated by two methods. The first is hydrogenation of a CO surface. The second is co-injection of CO molecules and H atoms. Both methods have been performed at 3 and 10 K. In the first method, the interaction of H atoms with solid CO at 10 K shows that CO is consumed to form H(2)CO and CH(3)OH. No trace of species such as HCO and CH(3)O is detected. No product was observed when the same experiment was performed at 3 K. In the second method, when H and CO are codeposited at 10 K, HCO and CH(3)O are observed. In fact, the yield of these intermediate species depends on the amount of the H radicals interacting with CO molecules. At 3 K, the presence of H(2) in the solid screens the hydrogenation reaction. This causes a termination for the reaction in the stage of the formation of HCO and H(2)CO. At 10 K, H(2) cannot condense, and the reaction between CO and H is total. In this case, species such as HCO, H(2)CO, CH(3)O, and CH(3)OH are observed.