MEASUREMENT OF ANISOTROPY IN THE LATERAL MOMENTUM OF A VIBRATING ADSORBED MOLECULE - CO CU(110)/

Anisotropies in the frustrated translational mode of CO chemisorbed on Cu(110) have been measured for the first time, with energies of 4.9 m eV in the [1 (1) over bar 0] directions and 3.1 meV in the [001] direc tions. The measurements are made using a new time-of-flight ESDIAD (el ectron stimulated desorption ion angular distribution) method, permitt ing the resolution of bond directional effects and initial. state late ral momentum effects in ESDIAD patterns. These measurements provide a more detailed understanding of the librational potential energy well s hape than has been possible previously.