  We investigate the worldline quantum field theory (WQFT) formalism for
scalar-QED and observe that a generating function emerges from WQFT, from which
the scattering angle ensues. This generating function bears important
similarities with the radial action in that it requires no consideration of
exponentiation of lower-order contributions. We demonstrate the computations of
this generating function and the resulting scattering angle of a binary system
coupled to electromagnetic field up to the third order in the Post-Minkowskian
expansion (3PM).expansion (3PM).
