Department of Chemistry, University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0216, USA.
J Chem Phys. 2017 Sep 28;147(12):124304. doi: 10.1063/1.4986818.
We investigate the lifetimes of vibrational states of diatomic alkali-alkaline-earth cations to determine their suitability for ultracold experiments where long decoherence time and controllability by an external electric field are desirable. The potential energy and permanent dipole moment curves for the ground electronic states of LiBe, LiMg, NaBe, and NaMg are obtained using the coupled cluster with singles doubles and triples and multireference configuration interaction methods in combination with large all-electron cc-pCVQZ and aug-cc-pCV5Z basis sets. The energies and wave functions of all vibrational states are obtained by solving the Schrödinger equation for nuclei with the B-spline basis set method. To predict the lifetimes of vibrational states, the transition dipole moments, as well as the Einstein coefficients describing spontaneous emission, and the stimulated absorption and emission induced by black body radiation are calculated. Surprisingly, in all studied ions, the lifetimes of the highest excited vibrational states are similar to the lifetimes of the ground vibrational states indicating that highly vibrationally excited ions could be useful for the ultracold experiments requiring long decoherence time.
我们研究了双原子碱土金属阳离子振动态的寿命，以确定它们是否适合超冷实验，在超冷实验中，需要长的退相干时间和可通过外部电场控制。使用耦合簇加上单双和三以及多参考组态相互作用方法，并结合全电子 cc-pCVQZ 和 aug-cc-pCV5Z 基组，获得了 LiBe、LiMg、NaBe 和 NaMg 的基态电子态的势能和永久偶极矩曲线。通过求解核的薛定谔方程，使用 B-样条基组方法获得所有振动态的能量和波函数。为了预测振动态的寿命，计算了描述自发发射的跃迁偶极矩，以及爱因斯坦系数，以及由黑体辐射引起的受激吸收和发射。令人惊讶的是，在所研究的所有离子中，最高激发振动态的寿命与基态振动寿命相似，这表明高度振动激发的离子可能对需要长退相干时间的超冷实验有用。
