INFRARED CHEMILUMINESCENCE OF CO AND CO2 PRODUCED BY MOLECULAR-BEAM SURFACE-REACTIONS

Vibrationally excited molecules produced by molecular-beam surface reactions have been studied by using infrared emission spectroscopy. The product CO desorbed by partial oxidation of n-butane on Pt at 1500 K is substantially vibrationally excited, but rotationally very cool (rotational temperature; T(R) = 360 K), while the product CO2 desorbed by the CO + O2 reaction on Pt is both vibrationally and rotationally excited. The CO2 molecules produced by CO oxidation on Pt using an atomic oxygen beam are much more highly excited (both vibrationally and rotationally) than those by the CO + O2 reaction. These results showed that both reactant and product molecules do not necessarily thermally accommodate to the sur-face, and their energy distributions will give us information on the dynamics of surface-catalyzed reactions.