Ottaviano-Fabrizio Mossotti (18 April 1791 – 20 March 1863) was an Italian physicist exiled from Italy for his liberal ideas. He later taught astronomy and physics at the University of Buenos Aires. His name is associated with a type of multiple-element lens correcting spherical aberration and coma, but not chromatic aberration. His studies on dielectrics lead to important results: the Clausius-Mossotti formula is partly named after him, and his view on dielectric behavior lead James Clerk Maxwell to devise his displacement current which, included in his equations lead to the theoretical intuition of electromagnetic waves.
Mossotti was Chair of Experimental Physics in Buenos Aires (1827–1835) and taught numerous Argentinian physicians his views on dielectrics, thereby becoming influential on the Argentine-German neurobiological tradition as regards electricity inside brain tissue, and later (after 1906) on this tradition's models of stationary waves in the interference of neural activity for short-term memory. He returned to Italy, participated in military actions after his age of sixty, and was appointed as Senator. There Mossotti also was influential on Hendrik Lorentz's views on fundamental forces, as well as more than five hundred mathematician students.