▎ 摘　　要

With the aid of ab initio, parameter free calculations based on density-functional and many-body perturbation theory, we investigate the electronic band structure and electron affinity of diamond surfaces. We focus on clean, ideal (0 0 1) and (1 1 1) surfaces and on the effect of hydrogen adsorption. Also single sheets of graphane, that is graphene functionalized upon hydrogen, are investigated. At full H-coverage nearly free electron states (NFESs) appear near the conduction band minimum in all the systems under study. At the same time, the electron affinity is strongly reduced becoming negative for the hydrogenated diamond surfaces, and almost zero in graphane. The effects of quasi-particle corrections on the electron affinity and on the NFESs are discussed.