Heteroepitaxial growth of LiF on LiBr or NaCl has been investigated by using reflection high-energy electron diffraction, Auger electron spectra, electron energy loss spectra and ultraviolet photoelectron spectra. In the case of LiF on LiBr, [100] axis of LiF is parallel to [100] axis of LiBr, while LiF grows on NaCl with [100](Lif)\\[100](NaCl). The azimuthal rotation of the film relative to the substrate has not been observed in other alkali halide heterostructures. The 45degrees rotation seems to come from two factors, the difference in lattice constants and the difference in ionic radii. The former is considered to relate to lateral matching, while the latter with vertical matching. A new loss peak was observed at about 7eV only for LiF/LiBr. The new loss peak seems to reflect the electronic state of the pseudo-LiBr molecule formed at the LiF/LiBr interface. (C) 2002 Elsevier Science B.V. All rights reserved.