The rotational analysis of the A(2)Pi(r)-X-2 Sigma(+) band system of MgBr

T Hirao, B Pinchemel, P F Bernath

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The A(2)Pi-X(2)Sigma(+) emission spectrum of the magnesium monobromide radical, MgBr, has been recorded with a Fourier transform spectrometer modified to record double-sided interferograms. The emission spectra of the Delta v = -2, -1, 0, +1 bands were generated in a microwave discharge of a mixture of argon and vaporized MgBr2. The Delta nu = 0 and -1 bands were rotationally resolved, but the F-2 spin component (A(2)Pi(3/2)) in the (1, 1), (1, 2) and vibrational bands with nu' > 1 were missing in our spectra because of a strong predissociation in the A state. The molecular constants in both electronic states were determined for the two bromine isotopomers. The r(o) bond length in the A state is about 2.327 Angstrom, which is about 0.02 Angstrom shorter than in the ground state. Franck-Condon factors were calculated from the Rydberg-Klein-Rees potentials, and they reproduce the observed relative intensities of the bandheads. An upper limit for the dissociation energy (D-o(o)) was obtained as 26 268.4 cm(-1), based on the absence of the energy level with nu = 1, A(2)Pi(3/2), J = 1.5 in our spectrum. (C) 2000 Academic Press.

Original languageEnglish
Pages (from-to)213-222
Number of pages10
Issue number2
Publication statusPublished - Aug 2000


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