Pair Production by Photons: Exact Calculation for Unscreened Atomic Field

Exact relativistic Coulomb wave functions, in the form of partial-wave expansions, are used to obtain analytic formulas for the differential cross sections and energy spectrum for electron-positron pair production by photons. Radiative corrections, which are believed to be small (of the order of 1%), are neglected. The errors introduced by the finite nuclear size and recoil effects are quite negligible for the energy region considered here....