2006 August-to date: Georgetown University, Washington, D.C.
2005 August-2006 August: The City College of the City University of New York, New York
2002 March-2005 August: National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Japan
1996 September-2002 February: Photochemistry Research Unit, Regional Research Laboratory (CSIR), Trivandrum, India