The spectral momentum density of amorphous-carbon

The properties of solids are largely determined by the motion of bound electrons. To understand the manifold nature of materials, an accurate knowledge of electron wave functions is required. In an (e, 2e) experiment the reaction kinematics are completely determined, and it is possible to perform direct measurement of the spectral momentum density of electrons in the target material. This quantity is proportional to the square of the target electron wavefunction represented in momentum space. In this paper, we present results obtained from an amorphous carbon film of thickness 80 angstrom. Using coplanar symmetric geometry and an incident beam energy of 10 keV, we have obtained binding energy spectra over a range of target electron momenta. Contributions from pi- and sigma-bands are clearly seen, demonstrating the feasibility of our approach. Previous coincidence measurements on solids have all suffered from poor energy resolution. Using multichannel collection techniques, we have achieved improved energy resolution whilst maintaining data collection rates