Wang Qin, Hou Shunyong, Xu Liang, Yin Jianping
State Key Laboratory of Precision Spectroscopy, Department of Physics, East China Normal University, Shanghai, 200062, P. R. China.
Phys Chem Chem Phys. 2016 Feb 21;18(7):5432-43. doi: 10.1039/c5cp06392b. Epub 2016 Jan 29.
To meet some demands for realizing precise measurements of an electric dipole moment of electron (eEDM) and examining cold collisions or cold chemical physics, we have proposed a novel, versatile electrostatic Stark decelerator with an array of true 3D electric potential wells, which are created by a series of horizontally-oriented, U-shaped electrodes with time-sequence controlling high voltages (± HV) and two guiding electrodes with a constant voltage. We have calculated the 2D electric field distribution, the Stark shifts of the four lowest rotational sub-levels of PbF molecules in the X1(2)Π1/2(v = 0) electronic and vibrational ground states as well as the population in the different rotational levels. We have discussed the 2D longitudinal and transverse phase-space acceptances of PbF molecules in our decelerator. Subsequently, we have simulated the dynamic processes of the decelerated PbF molecules using the 3D Monte-Carlo method, and have found that a supersonic PbF beam with a velocity of 300 m s(-1) can be efficiently slowed to about 5 m s(-1), which will greatly enhance the sensitivities to research a parity violation and measure an eEDM. In addition, we have investigated the dependences of the longitudinal velocity spread, longitudinal temperature and bunching efficiency on both the number of guiding stages and high voltages, and found that after bunching, a cold packet of PbF molecules in the J = 7/2, MΩ = -7/4 state with a longitudinal velocity spread of 0.69 m s(-1) (corresponding to a longitudinal temperature of 2.35 mK) will be produced by our high-efficient decelerator, which will generate a high energy-resolution molecular beam for studying cold collision physics. Finally, our novel decelerator can also be used to efficiently slow NO molecules with a tiny electric dipole moment (EDM) of 0.16 D from 315 m s(-1) to 28 m s(-1). It is clear that our proposed new decelerator has a good slowing performance and experimental feasibility as well as wide applications in the field of precise measurements and cold molecule physics.
为了满足实现电子电偶极矩（eEDM）精确测量以及研究冷碰撞或冷化学物理的一些需求，我们提出了一种新颖、通用的静电斯塔克减速器，它具有一系列真实的三维电势阱，这些电势阱由一系列水平排列的U形电极产生，通过时序控制施加高电压（±HV），还有两个施加恒定电压的导向电极。我们计算了二维电场分布、处于X1(2)Π1/2(v = 0)电子和振动基态的PbF分子四个最低转动子能级的斯塔克位移以及不同转动能级的布居数。我们讨论了PbF分子在我们的减速器中的二维纵向和横向相空间接受度。随后，我们使用三维蒙特卡罗方法模拟了减速后的PbF分子的动态过程，发现速度为300 m s(-1)的超音速PbF束可以有效地减速到约5 m s(-1)，这将大大提高研究宇称破坏和测量eEDM的灵敏度。此外，我们研究了纵向速度展宽、纵向温度和聚束效率对导向级数和高电压的依赖性，发现聚束后，我们的高效减速器将产生处于J = 7/2，MΩ = -7/4态的PbF分子冷包，其纵向速度展宽为0.69 m s(-1)（对应纵向温度为2.35 mK），这将产生用于研究冷碰撞物理的高能量分辨率分子束。最后，我们的新型减速器还可用于将具有0.16 D微小电偶极矩（EDM）的NO分子从315 m s(-1)有效地减速到28 m s(-1)。显然，我们提出的新型减速器具有良好的减速性能和实验可行性，在精确测量和冷分子物理领域具有广泛的应用。
