it is ejected with zero velocity along the radial direction.
Only if the big particle and the photon is of the same charge, repulsive, does the photon gain velocity in the radial direction.
If the big particle is positive aψ>aψne, then the photon has to be aψ≥aψne. Only after with some initial velocity, does the dipole spins and be self-propelling. (Post "Ladies and Gentlemen, We Have Light Speed!" 29 May 2014.)
A negative particle will not propel a ejected torus. The torus is likely to be reabsorbed.
...and we have a two color world; black and white.
How many shades of greys are in aψne≤aψtorus≤aψπ under normal conditions. Maybe aψtorus>aψne is in the infra-red. And ultra-violet is when aψtorus<aψne gains some initial speed by collisions or somehow.
...and we have colors.