The effects of surface additives on the chemistry of CH3 on Rh(111) as studied by reflection absorption infrared spectroscopy

The adsorption of gaseous CH3 on clean and modified Rh(111) has been studied using reflection absorption infrared spectroscopy and thermal desorption spectroscopy. It was found that preadsorbed K adatoms markedly stabilized the CH3 on Rh(111) and increased its stability by >100 K. This stabilization effect was attributed to the formation of a surface compound between CH3 and K. In contrast, coadsorbed Zn and I adatoms caused only very slight stabilization of CH3 on Rh due to the site blocking effect. The formation of methoxy species was observed in the CH3+O coadsorbed layer on Rh(111). The reaction pathways of surface complexes were also determined.