Dissociation of virtual photons, {\gamma }^* p \rightarrow Xp, has been studied in ep interactions with the ZEUS detector at HERA. The diffractive cross section, d\sigma _{\gamma ^*p}/dM_X, is presented as a function of the photon virtuality, Q². The W dependence of the diffractive and the total cross section is compared. The dependence of the diffractive structure function, F₂^D(3), on \beta , the Pomeron momentum fraction probed by photon, is also studied. The data are compared to predictions based on dipole models.

PACS numbers: 01.30.Cc, 25.40.Ep, 13.60.Hb, 42.25.Fx