ENHANCED NONLINEAR-OPTICAL RESPONSE OF AN ENDOHEDRAL METALLOFULLERENETHROUGH METAL-TO-CAGE CHARGE-TRANSFER

A new mechanism for increasing the third-order nonlinear optical susce ptibility, X-(3), is described for endohedral metallofullerenes. A two to three orders of magnitude increase in the nonlinear response is re ported for degenerate four-wave mixing experiments conducted with solu tions of Er-2@C-82 (isomer III) relative to empty-cage fullerenes. A v alue of - 8.7x 10(-32) esu is found for the molecular susceptibility, gamma(xyyx), of Er-2@C-82 compared to previously reported values of ga mma(xxxx) = 3 x 10(-34) esu and gamma(xyyx) = 4 x 10(-35) esu for C-60 . The results confirm the importance of the metal-to-cage charge-trans fer mechanism for enhancing the nonlinear optical response in endohedr al metallofullerenes. (C) 1998 American Institute of Physics.