Electric field effects in the chemisorption of CO on bimetallic RhCu surface models

Cluster models and hybrid density functional theory calculations are used to study the effect of an external electric field on the properties and bonding mechanism of CO on various RhCu bimetallic surfaces. The presence of an external electric field induces changes in the geometry and vibrational frequency of the chemisorbed molecule. Several methods of analysis establish that the electric field effects are not just of electrostatic nature but do affect the bonding mechanisms as well. In any case, the electric field effects observed for various RhCu bimetallic surfaces are not at all different from what is known for monometallic surfaces. The present study permits to conclude that the effect of an external electric field on the properties of CO adsorbed on bimetallic RhCu surfaces of different composition follows the same trend exhibited by the single metal surfaces.