Abstract
The first analysis of the electronic configuration at the surface of a monocrystal using low-energy positron diffraction (LEPD) is presented. This is done in conjunction with a standard structure determination for the GaAs(110) surface. Such as extension of the possibilities of LEPD is made possible by the use of the finite-difference method formalism. In addition to the improvement of the experiment-theory agreement for diffracted beam intensities, this technique provides a real cartography in three dimensions of the electronic density in the first atomic layers.