Abstract

Chemiexcitation of metastable electronic states of atoms and small molecules has been suggested as a means of achieving efficient, cw laser operation in the visible (and near-IR and UV) wavelength region. The present research is part of an ongoing effort aimed at providing guidelines for obtaining excitation of metastable states via collisions with singlet molecular oxygen. The low excited states of the bismuth atom, belonging to the p³ ground-state configuration, are metastable with transition probabilities ⩽120 s⁻¹. These metastable states can be populated as a result of one to three fruitful collisions of a ground state atom with an O₂(¹Δ) (E = 7882 cm⁻¹) and/or O₂(¹∑) (E = 13,121 cm⁻¹) molecules. Some of these collisional energy transfer steps are highly resonant. O₂ (¹Δ) and (¹∑) can similarly populate electronic states of Bi₂ and BiO. This paper reports on preliminary studies of reactions of O₂(¹Δ) and (¹∑) with Bi vapor. Mechanisms for production of excited species in Bi/O₂ mixtures are inferred from the dependence of the intensity of the emission from these species on the concentration of Bi atoms and Bi₂ molecules.

© 1986 Optical Society of America