Reply to "Comment on 'Magnetoelastic model for the relaxation of lanthanide ions in YBa2Cu3O7-delta observed by neutron scattering' " - art. no. 066502

The influence of lattice vibrations and charge fluctuations on the lifetime of crystal-field states is discussed in the context of experimental studie s of lanthanide ions in YBa2Cu3O7-d. Apart from S-state ions, lattice vibra tions always provide channel for relaxation, and, through the agency of an intermediate-energy crystal-field state, a significant contribution to the lifetime. In consequence, it is an unsafe practice to interpret the measure d lifetime of lanthanide ion crystal-field states in terms of scattering by charge carriers ignoring a lattice contribution. Certainly, it is a bad pr actice when the host material is a poor metal, like YBa2Cu3O7-d, and the de nsity of charge carriers is small.