Electron translation phase factors

In 'On the quantum mechanics of particles with classically assigned traject ories', Barton and Calogeracos (1996 Proc. R. Sec. A 452 1167) find that th e wavefunction surprisingly acquires an overall phase factor of the form ex p(+i integral (t)(0) E(t') dt'), surprising in that the conjugate was expec ted, with E the relative kinetic energy. It is shown that, with the correct interpretation in terms of electron translation phase factors, there is no surprise and the effect is well known experimentally and theoretically in charge transfer and ionization in ion-atom collisions.