  A metallic electron system near an orientational symmetry breaking
Pomeranchuk instability is characterized by a ''soft'' Fermi surface with
enhanced collective fluctuations. We analyze fluctuation effects in a
two-dimensional electron system on a square lattice in the vicinity of a
Pomeranchuk instability with d-wave symmetry, using a phenomenological model
which includes interactions with a small momentum transfer only. We compute the
dynamical density correlations with a d-wave form factor for small momenta and
frequencies, the dynamical effective interaction due to fluctuation exchange,
and the electron self-energy. At the quantum critical point the density
correlations and the dynamical forward scattering interaction diverge with a
dynamical exponent z=3. The singular forward scattering leads to large
self-energy corrections, which destroy Fermi liquid behavior over the whole
Fermi surface except near the Brillouin zone diagonal. The decay rate of
single-particle excitations, which is related to the width of the peaks in the
spectral function, exceeds the excitation energy in the low-energy limit. The
dispersion of maxima in the spectra flattens strongly near those portions of
the Fermi surface which are remote from the zone diagonal.
