  We compute the contribution to the two-body scattering angle of a specific
class of interactions involving the exchange of gravitational radiative degrees
of freedom, including the nonlinear memory process and square of radiation
reaction effects. Our computation is performed directly from the equations of
motion, thus computing the overall effect of both conservative and dissipative
processes. Such contributions provide in principle the last missing ingredients
to compute the scattering angle at fifth post-Newtonian, at fourth
post-Minkowskian order.
