Knowledge Bank

The emission of oxyhydrogen and oxyacetylene flames has been studied under high resolution with a 15,000-line grating spectrometer and lead sulfide cell. Slits as narrow as $0.2cm-1$ could be employed. The water-vapor band, which in room-temperature absorption extends from about $1.80-1.96\mu$, is broadened in emission from $1.7-2.2\mu (5000-4550cm-1)$. Over 600 strong lines have been measured in this region, and a number of weaker, partially resolved lines appear reproducibly. The analysis of the rotational structures is progressing. Many lines of the (011-000) band agree with those found in laboratory and atmospheric $absorption,1$ when allowance is made for the greatly increased effective temperature, and many additional lines from higher energy levels may be identified. The principal series $J-J⟷(J+1)-(J+1)$ may be followed out to $J\prime =22$ in both the P and R branches. Corresponding, lines in the upper-state bands (021-010) and (031-020) have also been identified with somewhat lower intensity, and a few lines may be assigned to the (041-030), (111-100), and (012-001) bands.