  Neutrino-nucleus cross sections for the detection of atmospheric neutrinos
are calculated in relativistic impulse and random phase approximations. Pion
production is estimated via inclusive Delta-hole nuclear excitations. The
number of pion events can confuse the identification of the neutrino flavor. As
a further source of pions we calculate coherent pion production (where the
nucleus remains in the ground state). We examine how these nuclear structure
effects influence atmospheric neutrino experiments and study possible
improvements in the present detector simulations.
