KINETICS AND SPECTROSCOPY OF ELECTRONICALLY EXCITED BIO OBTAINED BY ENERGY-TRANSFER FROM METASTABLE O-2 .1. DEPENDENCE OF EXCITATION ON [O-2]

Excitation of electronic states of the BiO molecule in a mixture of Bi vapor and O2 ( 1Δ1Σ) was monitored as a function of the density of the O2 singlet states. Emission in the 300-900 nm wavelength region was studied under low resolution and assigned to the A(2Π1/2 ), B(4Σ.) and C( 2Δ3/2 ) states of BiO. The intensity of the emission from the A (ν≥14), B and C states increased while that from A(ν≤ 12) decreased with increasing O2 (1Δ) density suggesting that the excitation mechanism for these higher levels involves multiple collisions with O2 ( 1Δ ). Emission from BiO C and from several A,ν' and B,ν' states has been observed here for the first time. In addition, emission in the 1400-1600 nm region was observed and studied for the reaction of Bi and low density of O2 ( 1Δ) via Fourier transform spectroscopy and is tentatively assigned to previously unobserved low lying 1/2 and 3/2 states of BiO. It is suggested that these states may play a crucial role in the excitation mechanism of the higher states. © 1990 American Institute of Physics.