Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallée, France.
Phys Chem Chem Phys. 2013 Jan 21;15(3):824-31. doi: 10.1039/c2cp43576d.
Franzreb and Williams at Arizona State University detected recently the MgO(2+) molecular species in the gas phase. Here we report a very detailed theoretical investigation of the low-lying electronic states of this dication including their potentials, spin-orbit, rotational and radial couplings. Our results show that the potential energy curves of the dicationic electronic states have deep potential wells. This confirms that this dication does exist in the gas phase; it is a thermodynamically stable molecule in its ground state, and it has several excited long-lived metastable states. The potential energy curves are used then to predict a set of spectroscopic parameters for the bound states of MgO(2+). We have also incorporated these potentials, rotational and radial couplings in dynamical calculations to derive the cross sections for the charge transfer Mg(2+) + O → Mg(+) + O(+) reaction in the 1-10(3) eV collision energy domain via formation-decomposition of the MgO(2+) dication. Our work shows the role of MgO(2+) in the Earth ionosphere and more generally in atmospheric processes in solar planets, where this reaction efficiently participates in the predominance of Mg(+) cations in these media compared to Mg and Mg(2+).
亚利桑那州立大学的 Franzreb 和 Williams 最近在气相中检测到了 MgO(2+) 分子物种。在这里，我们报告了对这个二价阳离子的低能电子态进行了非常详细的理论研究，包括它们的势能、自旋轨道、旋转和径向耦合。我们的结果表明，二价阳离子的电子态势能曲线具有深的势能阱。这证实了这个二价阳离子确实存在于气相中；它在基态下是热力学稳定的分子，并且具有几个激发的长寿命亚稳态。然后，我们使用势能曲线来预测 MgO(2+) 的束缚态的一组光谱参数。我们还将这些势能、旋转和径向耦合纳入动力学计算中，通过 MgO(2+) 的形成-分解，推导了在 1-10(3) eV 碰撞能域内 Mg(2+) + O → Mg(+) + O(+) 电荷转移反应的截面。我们的工作表明了 MgO(2+) 在地球电离层中的作用，更普遍地说，在太阳行星的大气过程中，与 Mg 和 Mg(2+) 相比，这种反应有效地参与了这些介质中 Mg(+) 阳离子的优势。
