Knowledge Bank

The absorption and emission spectrum, optical rotatory dispersion and circular dichroism of camphorquinone, a rigid molecule containing the four atom system of carbon and oxygen common to biacetyl, glyoxal and a host of similar compounds, exhibit two relatively weak and three stronger transitions between 20,000 and $56,000cm-1$. The longest wavelength transition is related to that of the symmetry forbidden $29,400cm-1$ transition of formaldehyde. The first two transitions contain most of the rotational strength of the corresponding long wavelength transition of the mono-ketone, camphor. The second transition is uniquely sharp at room temperature and exhibits a rather long vibrational progression indicating the possibility of a change in geometry of the upper state.