OPTICAL-RESPONSE OF NA CLUSTERS ON NACL SURFACES

We consider Na clusters on NaCl surfaces as examples of metal clusters attached to an insulating substrate. We concentrate on the cases Na, and Na, where three-dimensionally extended clusters compete with plana r clusters and compute the optical response of ground states and isome rs using the time-dependent local-density approximation. The interface interaction leads to strong deformations of the deposited clusters. N onetheless, one sees a well-developed plasmon response which allows co nclusions to be made on the underlying cluster structure (planar or th ree-dimensional). (C) 1998 Elsevier Science B.V. All rights reserved.