【作者】 曹红军；

【导师】 印建平；

【作者基本信息】 华东师范大学 ， 光学， 2011， 硕士

【摘要】 在过去的几十年里,原子与分子物理进入壮观的发展阶段,新颖的气体原子和分子冷却技术发挥着关键的作用。冷原子与冷分子的研究使得原子物理与分子物理连成一体,同时将物理领域与化学领域更紧密地连起来。超冷原子与冷原子有着许多共同的优势,冷分子和超冷分子在不久的未来会进一步提升基础研究领域的探测精度。分子比原子有更多的自由度,这样分子一方面增加了实验过程中操控分子的复杂性,然而分子在这些复杂性的对面,它为基础领域的精密测量和量子操控拓展了广阔的操作空间。本文首先综述了冷分子和超冷分子的基本理论知识,冷分子和超冷分子的产生方案和进展及其应用。其次,我们提出了基于两根载荷长直导线和两平行电极板实现极性分子表面弯曲导引的新方案,计算了芯片表面的空间电场强度分布,并以ND3为研究对象,计算了不同转动态的布居,计算相应的斯塔克势分布；计算并分析了该方案导引中心位置与电势参数和几何参数关系,研究了空间电场分布与各参数的依赖关系；利用蒙特卡罗方法模拟了极性分子的直导引和弯曲导引,最后给出了导引后分子束的温度。再者,我们利用缓冲气体冷却和静电弯曲导引实验装置产生冷分子,在室温下进行多种分子(多原子分子、对称和非对称陀螺分子)两次静电弯曲导引实验的研究,又进行CH3F缓冲气体冷却后两次静电弯曲导引实验的研究,研究了导引信号强度与导引电压、分子样品流量和He气体流量的关系。我们研究的方案可以进行弱场搜寻态分子的导引与操控,还可以构建各特定的光学分子仪器：例如不同半径分子速度滤波器和分子存储环；缓冲气体冷却和弯曲导引可以将分子的平动温度冷却至2K,其内态温度更低,为冷分子的存储与囚禁以及进一步实验研究奠定了基础。更多还原

【Abstract】 Over the last decades, atomic and molecular physics has come into a spectacular bloom, the newfashioned techniques to translationally cool (or slow down) gas atoms and molecules play unique roles in a number of diverse areas of fundamental interest. The study of slow atoms and molecules has led to uncharted territories ---- not just of atomic and molecular physics, but of physics at large. Cold molecules inspire many scientists. Ultracold atoms and cold atoms have many advantages in common, cold molecules and ultracold molecules in the near future, will further enhance the detection accuracy of basic research. Molecules have more freedom than atoms, molecules on the one hand increase difficulties in the process of the experimental controlling molecular; On the other hand, these complex molecules lay expansional fundation for precision measurement and quantum control. We compare the molecular and atomic, cold molecules can further develop many very interesting researches, what a pity, atoms does not own. Cold molecules reach a new height in basic research.In this paper, firstly, we review the basic theoretical knowledge of the ultra-cold molecules and cold molecules, the experimental generation and recent progress of cold molecules and ultra-cold molecules and their application. Secondly, we propose a novel scheme guiding cold polar molecules on the surface of a molecular chip by an electrostatic field generated by the combination of two parallel charged wires and sheets, and perform careful researches on our scheme to realize guiding for cold polar molecules. We also calculate the spatial distributions of the electric fields and their stark potential for ND3 molecules. Then we analyze the relationships between the electric field and the geometric parameters of two parallel charged sheet-wire system; we calculate and study the straight and bent guiding cold polar molecules by Monte-Carlo simulation. The transverse and longitudinal velocity distributions of the output guided molecular beam are simulated.We also generate cold molecules by stark velocity filter at room temperature. The buffer gas cooling technique is combined with the Stark velocity filter, obtaining a translationally and rotationally cold molecular (CH3F) beam. We measure the flux dependence and temperature of the filtered molecular beam on the guiding voltage, as well as on the reservoir pressure, and compare experimental results with simulation and that of other groups.Our study shows that we can use the proposed two parallel charged sheet-wire scheme to realize the manipulation and control of cold polar molecules in our surface guide on a chip and form special molecule elements, such as molecule storage ring and molecule velocity filter. The lowest attainable translational temperature of the cold molecules generated by buffer gas cooling combined with velocity filtering is about 1K, and their internal temperature is lower. The prospects and the future applications to studies of new physics and cold chemistry are presented, as well as future developments of researches on cold molecules in our lab. It lays foundation for trapping and storage of molecules and so on.更多还原