Knowledge Bank

High-resolution laser excitation spectroscopy has been employed for the first time to examine the $A1\Sigma +-X1\Sigma +$ system of CaS. Gaseous CaS was produced in a Broida-type oven by the reaction of calcium metal vapor with OCS. A Coherent 699-29 ring dye laser operating in single-frequency mode was used to investigate the rotational structure of the $A-X$ transition. The present work extends the lower resolution work of Blues and $Barrowa$ on the same system to higher vibrational levels and has allowed the indentification of several level crossings that occur in the $A1\Sigma +$ state. The deperturbation analysis of the $A-X$ transition will be discussed.