A quantum chemical investigation of imide adsorption at model Cu(110) surfaces

Abstract

The adsorption of imide (NH) on small clusters of copper atoms representing a Cu(110) surface has been investigated using density functional methods. The calculations show that the imide adsorbs in the short bridge site with a Cu–N distance of 1.856 Å and an N–H bond length of 1.031 Å. The formation of imide "‘chains’' in the 〈110〉 direction gives additional stabilisation where the imide spacing within the chains is 5.1 Å (i.e. two copper lattice spacings). An isolated imide prefers a linear geometry with the N–H bond orientated perpendicular to the surface plane but in the chains further stabilisation is obtained if the imides are tilted alternately in the 〈100〉 direction. Despite the relatively small cluster sizes used, the results show very good agreement with experimental results and help elucidate some experimental observations.