Laser-induced atomic fragment fluorescence spectroscopy: A facile technique for molecular spectroscopy of spin-forbidden states

Abstract

Spectra of spin-forbidden and spin-allowed transitions in the mixed b (3)Pi(u) approximately A (1)Sigma(u)(+) state of Na(2) are measured separately by two-photon excitation using a single tunable dye laser. The two-photon excitation produces Na(*)(3p) by photodissociation, which is easily and sensitively detected by atomic fluorescence. At low laser power, only the A (1)Sigma(u)(+) state is excited, completely free of triplet excitation. At high laser power, photodissociation via the intermediate b (3)Pi(u) triplet state becomes much more likely, effectively "switching" the observations from singlet spectroscopy to triplet spectroscopy with only minor apparatus changes. This technique of perturbation-assisted laser-induced atomic fragment fluorescence may therefore be especially useful as a general vehicle for investigating perturbation-related physics pertinent to the spin-forbidden states, as well as for studying allowed and forbidden states of other molecules.

B-X and C-X Band Systems of CuCl Revisited: Laser-induced Fluorescence Study in 465–490 nm

“…Nevertheless, the presence of triplet-singlet transitions, forbidden by Hund's case (a) selection rules, suggests that there is considerable mixing of the triplet and singlet states. This implies that it may not be convincing to relocate the singlets ( Π -3 -As demonstrated in our recent work [12] on the well-known Na 2…”