The plasmon dispersion behaviour of several forms of disordered carbon
, including glassy carbon, amorphous carbon, C-60 and tetrahedral amor
phous carbon, has been investigated; the data are presented in the for
m of maps. Differences in bonding structure are reflected in changes i
n the plasmon dispersion behaviour. A simple model of the dispersion r
elation in which variation in the plasmon frequency is dependent on th
e momentum transfer to the power r shows that r decreases from 1.5 for
glassy carbon to 0.6 for tetrahedral amorphous carbon. These variatio
ns in r are interpreted in terms of changes in the electronic structur
e for the material. (C) 1998 Elsevier Science Ltd. All rights reserved
.