[1] Natl Inst Lasers Plasma & Radiat Phys, Atomistilor 409, Bucharest, Romania
[2] Univ Craiova, Fac Sci, Craiova 200585, Romania
[3] Univ Bucharest, Fac Chem, Dept Chem Technol & Catalysis, 4-12 Regina Elisabeta Bd, Bucharest 030018, Romania
[4] Johannes Kepler Univ Linz, Inst Chem Technol Inorgan Mat ICTAS, Christian Doppler Lab Combinatorial Oxide Chem, Altenberger Str 69, A-4040 Linz, Austria