As detected by Auger electron spectroscopy (AES), the interaction of a pure (100) LiF surface with an electron beam induces a loss of fluorine. Lithium atoms are oxidized in the vacuum ambient and the formation of lithium oxide Li2O has been characterized using electron energy loss spectroscopy (EELS) by typical structures at 18.6 and 10 eV. The loss of fluorine is associated with a decrease of the positive surface potential. The cathodoluminescence (CL) emissions detected in the 250–900 nm wavelength range at 3.8, 3.1, 2.3 and 1.9 eV have been attributed to F, F3+and F2centers.