2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/220505We calculate the photon emission rate from a general atomic system in the mass- proportional CSL model. For an isolated charged particle emitting kilovolt gamma rays, our results agree with those obtained by Fu. For a neutral atomic system, photon emission is strongly suppressed for photon wavelengths much larger than the atomic radius. However, for kilovolt gamma rays, Fu's result is modified by a structure factor that is of order unity, giving no rate suppression. Our calculation is readily generalized to the case of non-white noise, noise couplings that are not mass-proportional, and general (non-Gaussian) spatial correlation functions, and corresponding results are given. We briefly discuss the implications of our calculation for upper bounds on the CSL model parameters.LaTex 16pages; minor revisions in published version v3, Added Note in v4Quantum PhysicsAstrophysicsHigh Energy Physics - PhenomenologyHigh Energy Physics - Theorytext