Electronic states and spectra of BiTe

Abstract

NIR/VIS emission spectra of the bismuth telluride radical, BiTe, were measured in the 3600–20 000 cm −1 region with a Fourier-transform spectrometer. BiTe was produced by reaction of bismuth and tellurium vapors and excited by energy transfer from metastable oxygen O 2( a 1Δ g) in a fast-flow system. The spectrum of BiTe was found to be markedly different from those of the previously studied BiO, BiS and BiSe radicals. The A 2 4Π 1/2 → X 1 2Π 1/2 transition which forms the most prominent and extended band system in these molecules was not observed for BiTe, and the X 2 2Π 3/2 → X 1 2Π 1/2 fine structure transition shows up with a different structure and at much lower wavenumbers than in the spectra of the lighter bismuth chalcogenides. The only common feature is the C 1 4Σ − 1/2 → X 1 2Π 1/2 system which is found in the range 16 500–19 000 cm −1 similar to the three other molecules. Besides the X 2 → X 1 and C 1 → X 1 systems, seven other transitions show up by short Δ ν = 0 sequences only. With help of the data derived from the analyses of the X 2 → X 1 and C 1 → X 1 systems and theoretical predictions of electronic and vibrational energies and transition probabilities of the strongest transitions of BiTe by Lingott et al. [7] the spectra were assigned to the transitions C 1 4Σ − 1/2 → X 2 2Π 3/2, C 1 4Σ − 1/2 → A 2 4Π 1/2, A 4 4Π 1/2 → A 2 4Π 1/2, A 4 4Π 1/2 → X 2 2Π 3/2, B 1 2Π 1/2 → A 2 4Π 1/2, B 1 2Π 1/2 → A 1 4Π 3/2, and B 2 2Π 3/2 → X 2 2Π 3/2.