Electronic Structure of Unoccupied States of Fluorinated Fullerenes C60F18 and C60F36

Comparative study of near edge X‐ray absorption fine structure spectra (NEXAFS) of fluorinated fullerenes C60Fx (x  =  0, 18, 36) has been implemented. Local density of unoccupied states was obtained and an accurate boundary between π* and (π+σ)* states was determined. The experimental evidence was found that unoccupied π*‐ states of C60Fx are delocalized ones and form cluster shells that sequentially disappear in fluorination starting from the highest state. As a result, the density of the lowest π* ‐ state (LUMO) was revealed to remain being constant in fluorination despite the π ‐electron subsystem exhaustion.