The Be electron inelastic mean free path (IMFP) is calculated by using the GW approximation of many-body theory. It is demonstrated that the inclusion of band structure effects significantly improves the agreement between the calculated and measured IMFP in the energy range up to $\sim 30\mathrm{eV}.$ We show that the main effect results from the electron group velocity obtained from ab initio band structure calculations, whereas the evaluated linewidth averaged over momenta is not significantly affected with respect to the prediction of a free electron gas model. The comparison of the IMFP computed within two models, namely, the free electron gas model and the full band structure model, supports the idea of the importance of band structure effects for the description of electron transport in this metal for energies below 30 eV, and a nearly free-electron-like behavior for excitation energies above 30 eV. The calculated plasmon dispersion is in excellent agreement with available experimental data.

• Received 14 July 2003

DOI:https://doi.org/10.1103/PhysRevB.68.205106