  We have carried out electron energy-loss investigations of the lowest singlet
excitons in pentacene at 20 K. Our studies allow to determine the full exciton
band structure in the a*,b* reciprocal lattice plane. The lowest singlet
exciton can move coherently within this plane, and the resulting exciton
dispersion is highly anisotropic. The analysis of the energetically following
(satellite) features indicates a strong admixture of charge transfer
excitations to the exciton wave function.
