The Spectrum of Sulphur Dioxide

A study has been made of the emission and absorption spectrum of sulphur dioxide with special emphasis on the region from 2000 to 2600A. It was found possible to run a discharge in flowing S${\mathrm{O}}_2$ with comparatively little dissociation. The work on absorption was supplementary to that on emission and carried out at the same moderate dispersion. A large proportion of both the emission and absorption bands found fit into a scheme of vibrational levels. The upper levels indicate a frequency of about 375 ${\mathrm{cm}}^{-1\mathrm{}}$ or an integral multiple of that value. The lower levels confirm the 1150 and 520 frequencies previously observed but leave the third frequency in doubt. The $x_e{\omega }_e$ for both the 1150 and 520 frequencies are small, of the order of one ${\mathrm{cm}}^{-1\mathrm{}}$ for the latter as determined from a progression of sixteen bands.