On the Silicon Oxide Bands

Abstract

Pankhurst has described a band spectrum believed by him to belong to an oxide of silicon, possibly Si${\mathrm{O}}_{2}$. A better excitation of the same bands has been obtained from a similar source (a high voltage uncondensed discharge through a constriction in a quartz tube), but in helium gas instead of hydrogen. These bands have been photographed on the 30-foot, 30,000 lines per inch Chicago grating spectrograph. A band near $\ensuremath{\lambda}3840$ has been resolved in the first and second orders and found to be a (0,0) transition, overlapped by a weak (1,1) transition, of the type $^{2}\ensuremath{\Sigma}\ensuremath{\rightarrow}^{2}\ensuremath{\Sigma}$, having the constants ${\ensuremath{\nu}(0,0)=26,015.05 {\mathrm{cm}}^{\ensuremath{-}1},,\ensuremath{\nu}(1,1)=25,991.44{\mathrm{cm}}^{\ensuremath{-}1},}{{{B}_{0}}^{\ensuremath{'}}=0.7180{\mathrm{cm}}^{\ensuremath{-}1},,{{B}_{1}}^{\ensuremath{'}}=0.704{\mathrm{cm}}^{\ensuremath{-}1},}{{{B}_{0}}^{\ensuremath{'}\ensuremath{'}}=0.7253{\mathrm{cm}}^{\ensuremath{-}1},,{{B}_{1}}^{\ensuremath{'}\ensuremath{'}}=0.712{\mathrm{cm}}^{\ensuremath{-}1}.}$ The coefficients of the spin doubling for the two states are ${{\ensuremath{\gamma}}_{0}}^{\ensuremath{'}}=+0.012 {\mathrm{cm}}^{\ensuremath{-}1}$, ${{\ensuremath{\gamma}}_{0}}^{\ensuremath{'}\ensuremath{'}}=+0.002$ or ${{\ensuremath{\gamma}}_{0}}^{\ensuremath{'}\ensuremath{'}}=+0.022 {\mathrm{cm}}^{\ensuremath{-}1}$, the value of ${{\ensuremath{\gamma}}_{0}}^{\ensuremath{'}\ensuremath{'}}$ not certainly fixed as between these two alternatives. The doublet structure and the $B$ values prove that the emitter is Si${\mathrm{O}}^{+}$. Other bands at $\ensuremath{\lambda}4270$ have been resolved with weak intensity and tentatively ascribed to Si${\mathrm{O}}_{2}$.