  The scattering of wavepackets with arbitrary energy dispersion on surfaces
has been analyzed. Expanding up to second order in scattering shifts, it is
found that besides the known Goos-H\"anchen or Imbert-Fedorov spatial offset,
as well as the Wigner delay time, new momentum and frequency shifts appear.
Furthermore, the width of the scattered wave packet becomes modified as well,
which can lead to a shrinking of pulses by multiple scattering. For a model of
dielectric material characterized by a longitudinal and transverse dielectric
function the shifts are calculated analytically. From the Goos-H\"anchen and
Imbert-Fedorov shifts one can access the longitudinal and transversal
dielectric function. Perfectly aligned crystal symmetry axes with respect to
scattering beam shows no Imbert-Fedorov effect. It is found that the
Goos-H\"anchen and Imbert-Fedorov effect are absent for homogeneous materials.
Oppositely it is found that the Wigner delay time and the shrinking of the
temporal pulse width allows to access the dielectric function independent on
the beam geometry.
