Quasiparticle dynamics on metal surfaces

Here we present a survey of current investigations of the quasiparticle dyn amics in 2D quantum states - surface and image potential states on metal su rfaces. The calculations of the lifetime of excited quasiparticle are perfo rmed within the GW approximation of many-body theory. We analyze the role o f the key ingredients of the quasiparticle dynamics, namely. the screened C oulomb interaction at metal surfaces and the overlap of the initial and fin al states and we show that both of these factors are essential for a proper description of the quasiparticle dynamics. (C) 2001 Elsevier Science B.V. All rights reserved.