FLUORESCENCE OF CaO (B-1 Pi -> X-1 Sigma(+)) IN A LASER-INDUCED PLASMA

The scheme of CaO molecular fluorescence in a laser-induced plasma involving transitions between B-1 Pi and X-1 Sigma(+) electronic states was proposed and implemented. CaO molecular bands in fluorescence spectra were observed at 408.43 (band 0, 1) and 421 nm. The band at 421 nm was assigned to the (0, 3) transition using vibrational level energies calculated by molecular constants. Selective excitation of rotational states was demonstrated and was observed as a shift of the fluorescence intensity maximum in the spectrum with a change of the exciting laser wavelength within the vibrational band. The proposed scheme for CaO fluorescence was used in spatially resolved measurements to show the distribution of calcium oxide molecules in the laser-induced plasma.