2005 - 2006 University of Florida, Chemistry Department, Group Leader in Computational Chemistry
2004 - 2005 University of Florida, Chemistry Department, Researcher
2003 - 2004 Tartu Ülikool, Keemilise Füüsika Instituut, EL 5RP TKV Imagetox stipendiaat
1999 - 2001 Bulgarian Academy of Sciences, Institute for Nuclear Research and Nuclear Energy, research fellow