Schemes for excitation of rare earth monoxides in flame laser-induced molecular ionization spectrometry

Laser-induced ionization spectra of PrO, TbO, and CeO molecules in a flame were recorded in the wavelength ranges 440–480 nm and 535–575 nm. Based on study of the spectra, we propose a two-step scheme for excitation of PrO and CeO molecules in which in the first step, the molecule goes to the excited electronic state, while the excitation energy in the second step is selected so that the total energy imparted to the molecule corresponds to its ionization potential.