The radiative electron capture in nonrelativistic atomic collisions is normally considered by using the Schrödinger equation. We show that the capture cross section obtained from this equation is Galilean-invariant. This result follows under quite general conditions and holds irrespectively of the accuracy of wave functions describing the charged particles. In contrast, this accuracy is crucial for gauge independence of the cross section and we demonstrate that it is the gauge dependence which has been misinterpreted for a long time as the Galilean noninvariance.

• Received 7 March 2006

DOI:https://doi.org/10.1103/PhysRevA.73.052714