Pali KPELOU

Department of physics, University of Lomé, Lomé, Togo

Gnande DJETELI

Department of physics, University of Lomé, Lomé, Togo

Tiburce Ahouangbe ABOKI

GMS-LPCS UMR7045 / Chimie Paristech Paris Cedex 05, France
Palais de la découverte / Universcience, Avenue Franklin Roosevelt, 75008 Paris, France

Ayi Djifa HOUNSI

Department of physics, University of Lomé, Lomé, Togo

Kossi NAPO

Department of physics, University of Lomé, Lomé, Togo