Department of Chemistry and Biochemistry, Department of Astronomy, and Steward Observatory, University of Arizona, 1305 E. 4th Street, Tucson, Arizona 85719, USA.
J Chem Phys. 2019 Jan 21;150(3):034303. doi: 10.1063/1.5079396.
The pure rotational spectrum of ZnBr (XΣ) has been recorded in the frequency range 259-310 GHz using millimeter-wave direct absorption techniques. This study is the first quantitative spectroscopic investigation of this free radical. ZnBr was synthesized in a DC discharge by the reaction of zinc vapor in argon with one of three reagents: BrCH, BrCH, or Br. Eight rotational transitions were measured for six isotopologues (ZnBr, ZnBr, ZnBr, ZnBr, ZnBr, and ZnBr), all of which exhibited spin-rotation interactions. Furthermore, transitions originating in the v = 1 through 3 excited vibrational states were obtained for certain isotopologues. Five rotational transitions were also recorded for ZnBr, in which hyperfine splittings were observed arising from the Zn nucleus (I = 5/2). The spectra were analyzed using a Hund's case (b) Hamiltonian, and rotational, spin-rotation, and Zn magnetic hyperfine constants were determined. Equilibrium parameters were also derived for the ZnBr, ZnBr, ZnBr, and ZnBr isotopologues, including the vibrational constant, ω = 286 cm. The equilibrium bond length was derived to be r = 2.268 48(90) Å. Analysis of the Zn hyperfine parameters suggest a decrease in ionic character in ZnBr from the other known zinc halides, ZnF and ZnCl.
采用毫米波直接吸收技术，在 259-310GHz 频率范围内记录了 ZnBr（XΣ）的纯旋转光谱。这项研究是对这种自由基的首次定量光谱研究。ZnBr 通过锌蒸气与氩气反应与三种试剂之一（BrCH、BrCH 或 Br）反应，在直流放电中合成。测量了六个同位素（ZnBr、ZnBr、ZnBr、ZnBr、ZnBr 和 ZnBr）的八个转动跃迁，所有这些跃迁都表现出自旋-转动相互作用。此外，还获得了某些同位素的 v = 1 到 3 激发振动态的转动跃迁。还记录了 ZnBr 的五个转动跃迁，其中观察到来自 Zn 核（I = 5/2）的超精细分裂。使用 Hund 案例（b）哈密顿量对光谱进行了分析，并确定了转动、自旋-转动和 Zn 磁超精细常数。还为 ZnBr、ZnBr、ZnBr 和 ZnBr 同位素导出了平衡参数，包括振动常数 ω = 286cm。导出的平衡键长为 r = 2.26848(90)Å。对 Zn 超精细参数的分析表明，ZnBr 中的离子性比其他已知的锌卤化物 ZnF 和 ZnCl 有所降低。
