关键词: Xe-NH体系/
感应冷却/
原子分子冷碰撞
English Abstract
Potential energy surface and cold collision dynamics of Xe-NH(X3∑-) system
Qiao Zheng1\21,2,Wang Ya-Li1,
Wu Ming-Wei1,
Feng Er-Yin1,
Huang Wu-Ying1
1.College of Physics and Electronic Information, Anhui Normal University, Wuhu 241000, China;
2.School of Common Courses, Wannan Medical College, Wuhu 241002, China
Fund Project:Project supported by the National Natural Science Foundation of China (Grant Nos. 10874001, 11374014).Received Date:09 July 2018
Accepted Date:03 September 2018
Published Online:05 November 2018
Abstract:Sympathetic cooling is one of the most promising techniques for producing ultracold molecules from precooled molecules. Previous researches have shown that it is inadequate to use the ultracold alkali-metal atoms as coolant for sympathetic cooling. To explore the possibility of ultracold alkali-earth-metal atoms as coolant, in this paper a theoretical investigation is performed of the cold collision dynamics for Xe-NH(X3∑-) system in magnetic fields. The interaction potential energies of Xe-NH complex are calculated respectively by using the single and double excitation coupled-cluster theory with the noniterative treatment of triple excitations[CCSD(T)] method and complete basis set limit extrapolated method. An analytic express of potential energy surface (PES) is given for the first time. A single global minimum value occurs at R=7.14a0, θ=102.76° with an energy of-153.54 cm-1, and the PES has a weak anisotropy. Combine the ab initio PES with quantum scattering theory, then the cold collisional dynamics of Xe-NH system in a magnetic field will be studied. The elastic and inelastic transition cross sections and their ratios of NH molecules in the lowest low-field following state (n=0, mj=1) under different magnetic fields and collisional energies are calculated. The results show that the elastic cross section is independent of magnetic field, and the inelastic cross section changes with magnetic field, especially at an ultracold temperature. A common rule of thumb is that to successfully implement cooling, the ratio of elastic cross section to inelastic cross section needs to reach 100 at least. The results suggest that it is likely to be a challenging work to perform sympathetic cooling of NH molecule by ultracold Xe atom.
Keywords: Xe-NH complex/
sympathetic cooling/
cold atom-molecule collision
