In this paper we present some new theoretical results from our study o
f a two-layer electron gas separated by a variable distance, based on
a model recently proposed by us (referred to as the CD model) and also
beyond that model. In a recent communication we derived analytical re
sults for the optical and acoustic plasmon modes in the presence of el
ectron impurity collisions on the layers and briefly presented an ener
gy loss function. The present paper contains results of our further ex
ploration of the CD model and a detailed consideration of the energy l
oss functions. We present plots for the loss functions and discuss the
prospects of experimentally observing the elusive acoustic plasmon. (
C) 1997 Academic Press Limited