Knowledge Bank

A rigid asymmetric rotor program is tested by calculating contours for bands of water vapor and sulfur dioxide. Contours for type A, B, and C bands calculated for a series of values of the excited state rotational constants are compared with observed contours of the 1240 {\AA} band of $H2O$ and the corresponding band of $D2O$. The previous assignment as a type C band is confirmed and a determination of the geometrical structure of the excited state is made. A type C band contour has been calculated for the 3880 {\AA} band of the absorption spectrum of $SO2$ vapor. In agreement with observation this contour shows an intense, sharp peak about $25cm-1$ toward the violet of the principal maximum. A previously calculated symmetric rotor contour does not show this peak. Supported by the Air Force Office of Scientific Research.