  Although the unified formula for gamma-ray absorption process involving both
the magnetic field and a perpendicular electric field derived by Daugherty &
Lerche (1975) is correct, we argued in this paper that their conclusion that
the induced electric fields are important in the pair formation process in the
pulsar magnetospheres is wrong and misleading. The key point is that usually
the direction of a gamma photon at the emission point observed in the
laboratory frame should be (v/c, 0, [1-(v/c)^2]^{1/2}) rather than (0, 0, 1),
where v is the co-rotating velocity. This emission direction is just the one
which results in zero attenuation coefficient of the gamma photon. Calculation
shows that after the photon has moved a distance, its direction lead to the
result that the induced electric field is also of minor importance. Thus only
gamma-B process is the important mechanism for the pair production in the
pulsar magnetospheres. The implications of the modification by ejecting the
induced electric field are also discussed.
