The electronic structures of ground state and electronic spectrum of C~6~0C(C=CH)~2 were calculated using INDO/2 and INDO/SCI methods. Furthermore,we designed molecule C~6~0(C=CH)~2 and calculated its electronic structure and spectrum using same methods. The calculated results agree fairly well with the experimental ones. The nonlinear second-order optical susceptibilities β~i~j~k and β~μ calculations have been performed using ZINDO-SOS method on the basis of the correct electronic spectra. Analysis and discussion fo the obtained results have been made. The conclusion is: C~6~0(C=CH)~2 with its diacetylene group directly bound to the [60] fullerene hase a bigger β value than C~6~0C (C=CH)~2 and therefore might be potential nonlinear optical material.

Key words: FULLERENES, ELECTRONIC SPECTROSCOPY, NON LINEAR OPTICS, INTERMEDIATE NEGLECT OF DIFFERENTIAL OVERLAP APPROXIMATION (IND, ELECTRONIC STRUCTURE, OPTICAL MATERIAL