Knowledge Bank

Several gases $CO2,CO,CH4,NO,SO2,H2O$, and $SiH4)$ have been added to a He flowing afterglow and the spectral emissions from the dissociation products have been observed from 3000 to 6000 \AA. $SiH4$ gave the most interesting spectrum, with abundant Si lines of SiI and SiII, and bands of $SiH+$ and SiH with the 4100 \AA SiH band being extremely intense. $SO2$ did not give an abundant spectrum becaus the most intense emission of SO is below the region studied. In CO the comet tail emission of $CO+$ was the principal emission with a few weak triplet emissions of CO. For $CO2$ there was an intense comet tail emission of $CO+$, the weak triplet emission of CO, and the intense many-band emission of Fox, Duffendack and Barker ‘s system of $CO2$. Only the $\beta$ system of NO was observed along with lines of the $N2$ second positive system. The 3064 \AA OH spectrum and the 3565 \AA $OH+$ spectrum were observed with the addition of $H2O$. With $CH4$ both the 4300 and 3900 \AA systems of CH were observed.