Characteristic Energy Loss of Electrons in Graphite

Abstract

The problem of analyzing the characteristic energy loss of electrons in solids is discussed in some detail. Based on the general discussion developed in Secs. 1 and 2, the observed 7.5-ev loss line of graphite is tentatively identified as due to the collective excitation of $\pi$ electrons. The theoretical analysis gives results which strongly favor this identification. Furthermore, it has been shown that the present theory together with detailed experimental studies is very useful for the determination of the $\pi$-electron band structure of graphite.