We propose a combined method to eciently perform ground- and excited-state calculations
for relaxed geometries using both a rst-principles approach and a classical molecular-dynamics
scheme. We apply this method to calculate the ground state, the optical properties, and the
electronic excitations of Ge nanoparticles embedded in a SiC matrix. Classical dynamics is used
to relax the large cell system. First-principles techniques are then used to calculate the electronic
structure and, in turn, the electronic excitations and optical properties. The proposed procedure
is tested with data resulting from a full rst-principles scheme. Good qualitative accordance has
been found between the results after the two computational paths regarding the structure, the
optical properties and even the electronic excitations
