  We introduce a model description of femtosecond laser induced desorption at
surfaces. The substrate part of the system is taken into account as a (possibly
semi-infinite) linear chain. Here, being especially interested in the early
stages of dissociation, we consider a finite-size implementation of the model
(i.e., a finite substrate), for which an exact numerical solution is possible.
By time-evolving the many-body wave function, and also using results from a
time-dependent density functional theory description for electron-nuclear
systems, we analyze the competition between several surface-response mechanisms
and electronic correlations in the transient and longer time dynamics under the
influence of dipole-coupled fields. Our model allows us to explore how coherent
multiple-pulse protocols can impact desorption in a variety of prototypical
experiments.
