  We propose a scheme for the construction of a CNOT gate by adiabatic passage
in an optical cavity. In opposition to a previously proposed method, the
technique is not based on fractional adiabatic passage, which requires the
control of the ratio of two pulse amplitudes. Moreover, the technique
constitutes a decoherence-free method in the sense that spontaneous emission
and cavity damping are avoided since the dynamics follows dark states.
