Hirao T, Pinchemel B, Bernath PF
Department of Chemistry, University of Waterloo, Waterloo, Ontario, N2L 3G1, Canada
J Mol Spectrosc. 2000 Aug;202(2):213-222. doi: 10.1006/jmsp.2000.8139.
The A(2)Pi(r)-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 Deltav = -2, -1, 0, +1 bands were generated in a microwave discharge of a mixture of argon and vaporized MgBr(2). The Deltav = 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 v' > 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(0) bond length in the A state is about 2.327 Å, which is about 0.02 Å 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(0)(0)) was obtained as 26 268.4 cm(-1), based on the absence of the energy level with v = 1, A(2)Pi(3/2), J = 1.5 in our spectrum. Copyright 2000 Academic Press.
利用一台经过改装以记录双面干涉图的傅里叶变换光谱仪，记录了溴化镁自由基（MgBr）的A(2)Pi(r)-X(2)Sigma(+)发射光谱。在氩气与汽化的MgBr₂混合气体的微波放电中，产生了Δv = -2、-1、0、+1各谱带的发射光谱。Δv = 0和-1的谱带得到了转动分辨，但由于A态存在强烈的预解离，我们的光谱中在(1, 1)、(1, 2)以及v' > 1的振动态谱带中缺少F(2)自旋分量（A(2)Pi(3/2)）。确定了两种溴同位素异构体在两个电子态下的分子常数。A态的r(0)键长约为2.327 Å，比基态短约0.02 Å。根据里德堡-克莱因-里斯势计算了弗兰克-康登因子，它们再现了观测到的谱带头相对强度。基于我们的光谱中不存在v = 1、A(2)Pi(3/2)、J = 1.5的能级，得到解离能（D(0)(0)）的上限为26268.4 cm⁻¹。版权所有2000年，学术出版社。
