 During 1983-1984, Rammal served as a visiting professor for six months in Nuclear Physics, co-managing the University of Pennsylvania in Philadelphia Research Department (United States) and Brookhaven National Laboratory in Upton, New York.He had also served as a visiting professor for another six months in the Department of Physics at the University of Sherbrooke in Quebec, Canada.During 1984-1986, he served as a research professor at the National Center for Scientific Research at the University of Grenoble.