Diffusion of the rare earth in natural and synthetic fluorapatite was characterized under anhydrous conditions. The Sm was introduced by means of ion implantation, with diffusivities being extracted by measurement of the relaxation of the implanted profile after diffusion anneals. The depth profiles were measured using Rutherford back-scattering spectrometry. The Arrhenius relation for 750 to 1100C was:

D(m2/s) = 6.3 x 10-7 exp[-298(kJ/mol)/RT]

D.J.Cherniak: Geochimica et Cosmochimica Acta, 2000, 64[22], 3871-85