THEORY OF NEGATIVE-ION FORMATION IN CO CHEMISORBED ON NI(110) - THE (2)SIGMA SHAPE RESONANCE

The lifetime, energy and angular distributions for resonance electron scattering by the (2) Sigma Shape resonance of CO chemisorbed on Ni(11 0) are calculated using a layer-KKR method. This calculation is based upon a multiple scattering approach to negative ion formation at surfa ces in which the substrate scattering is fully incorporated. The resul ts are compared to the experimental study of Jones et al. [Chem. Phys. Lett. 161 (1989) 467] and a prior coupled-angular-modes (CAM) study b y Teillet-Billy and coworkers that considered only the screening of th e negative ion by the metallic substrate [Nucl. Instrum. Methods 58 (1 991) 393].