Conformation of histidine model peptides. II. Spectroscopic properties of the imidazole chromophore

Semi‐empirical molecular orbital calculations have been carried out for the free base and cationic forms of imidazole so as to obtain data which are required for the calculation of the chiroptical properties of molecules that contain this chromophoric group. The polarization, energy, and monopolar charge distribution are reported for the lowest energy electronic transitions. The absorption spectra for imidazole have been determined to 180 nm and circular dichroism spectra for L ‐histidinol and L ‐2‐amino‐1‐butanol have been measured.