Remarks concerning pair creation in strong magnetic fields

We derive the probability and attenuation coefficients for pair creation in first order of polarized electrons and positrons. The positron and electron can occupy arbitrary Landau levels and the attenuation coefficient is evaluated for any direction and polarization of the photon. When we take theta = 90 degrees and sum over polarization of the spins of the e(+) - e(-) pair, we obtain results which differ from the expressions for the attenuation coefficient obtained by Daugherty & Harding (1983), by the factor (1 + delta (N,0))(1 + delta (N',0))/4, in agreement with Frangodimitraki-Georgiadou (1991).