1. a Department of Physics , University of Guelph , Guelph , Ontario , N1G 2W1 , Canada
2. c Department of Mechanical Engineering , S.U.N.Y. at Stony Brook , Stony Brook , N.Y. , 11794 , U.S.A.
3. b Departments of Mechanical Engineering and Chemistry , State University of New York at Stony Brook , Stony Brook , New York , 11794 , U.S.A.