  We search high-resolution and high-quality VLT/UVES optical spectra of the
hot R Coronae Borealis (RCB) star DY Cen for electronic transitions of the C60
molecule and diffuse interstellar bands (DIBs). We report the non-detection of
the strongest C60 electronic transitions (e.g., those at ~3760, 3980, and 4024
A). Absence of C60 absorption bands may support recent laboratory results,
which show that the ~7.0, 8.5, 17.4, and 18.8 um emission features seen in DY
Cen - and other similar objects with PAH-like dominated IR spectra - are
attributable to proto-fullerenes or fullerene precursors rather than to C60.
DIBs towards DY Cen are normal for its reddening; the only exception is the DIB
at 6284 A (possibly also the 7223A DIB) that is found to be unusually strong.
We also report the detection of a new broad (FWHM~2 A) and unidentified feature
centered at ~4000 A. We suggest that this new band may be related to the
circumstellar proto-fullerenes seen at infrared wavelengths.
