Relaxation of excited electrons in an electron gas: A mean-field approach with charge and spin polarizations

The relaxation rate of excited electrons in a paramagnetic electron gas is calculated. The theory is based on the charge and spin response functions and the local-field methodology of generalized mean-field descriptions. A link between this treatment and the kinetic treatment for the relaxation phenomena is established in the first-order Born limit. The relative weight of the spin-fluctuation channel in the important low-energy dynamics is quantified for our model system.