In pursuit of negative Fukui functions: molecules with very small band gaps.

A justification for the likely presence of negative Fukui functions in molecules with small band gaps is given, and a computational study performed to check whether molecules with small band gaps have negative Fukui functions to a chemically significant extent is reported. While regions with negative Fukui functions were observed, significantly negative values for the atom-condensed Fukui functions were not observed. [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]