Observation of terahertz vibrations in the nitrogenase FeMo cofactor by femtosecond pump-probe spectroscopy. - Delfino I; Cerullo G; Cannistraro S; Manzoni C; Polli D; Dapper C; Newton WE; Guo Y; Cramer SP (Angewandte Chemie (International ed. in English), 2010)