The structure and UV-vis spectra of a series of covalently linked C~6~0 Pyrrolidine/ferrocene(C~6~0Py/Fc) based Donor-Bridge-Acceptor(D- B-A) dyads were calculated using INDO/2 and INDO/CI methods. The calculated results are in good agreement with observasions. On the basis of the correct electromic spectra, calculations of the second- order susceptibilities β~i~j~k, β~μ of C~6~0PY/Fc were performed using the INDO/SCI method combined with a sum-over-state(SOS) expression. The micromechanism of the influence of the molecular electronic structures on β~μ was examined.

Key words: FULLERENES, PYRROLE, FERROCENE, ELECTRONIC STRUCTURE, NON LINEAR OPTICS, OPTICAL PROPERTIES, CHARGE TRANSFER, INTERMEDIATE NEGLECT OF DIFFERENTIAL OVERLAP APPROXIMATION (IND