The photon is emitted before the particle escapes (if it escapes) as,
|d2xdt2|−1mphotonψc<|d2xdt2|−1mψc
The photon escapes the particle tangentially and the particle escape ψ tangentially. Both will be in a spin of radius, if they escape,
r=1ψcmv2−uψc+u1eu(e2u−1)1/2
The ratio of energies,
ψcmv2
where
ψc=ψn−ψmax
ψn=ψphoton+ψo
ψn is the elevated energy level of the particle from its ground state ψo after receiving the photon ψphoton. ψmax is the maximum ψ of the confining particle cloud.
is most interesting. Given a non transit (confining) particle, the term,
uψc+u1eu(e2u−1)1/2
is fixed. It is also at maximum at the boundary of ψ(x). (To be proven...) The energy ratio, ψcmv2 determines the radius of the escape spin.
This is the second way, a particle goes into a spin. The first being on head on retardation by a temperature particle that stops the particle before collision, from the post "No Temperature Particle At All, Zero" date 12 Jul 2015.
Note:
Both transit and non-transit particles are of the same type, otherwise their energy densities would not interact. The non-transit particle is considered as an extended spherical ψ cloud around the particle center. It could be the superposition of many particles of the same type. The transit particle is considered as a point particle inside ψ of the non transit particle.