基于电子碰撞方法和光吸收方法的振子强度测量

发布时间：2018-03-11 05:11

  本文选题：振子强度　切入点：光吸收方法　出处：《中国科学技术大学》2017年硕士论文　论文类型：学位论文

【摘要】：振子强度是描写能级之间跃迁概率的物理量,属于物质在原子分子层面上的基本参数,在理论和实验上都极其重要。目前国际上对此物理量的测量准确度大约为10%。本实验室长期致力于研究提高振子强度测量的准确度。为了实现这一目的,实验室在完全自主搭建起高分辨快电子能量损失谱仪后,又增加了相对流量技术,建立了统一的数据绝对化标准。最近我们又基于X-ray散射技术首次提出了测量原子分子光学振子强度的diPole(γ,γ)方法。此外,我们还对测量光学振子强度的光吸收方法进行了探索和改进。本论文基于电子碰撞方法和光吸收方法,测量了原子分子的振子强度,取得了一些成果。本论文分为两大部分,第一部分是基于电子碰撞方法展开的研究,主要包括:利用电子能量损失谱仪在入射电子能量1500eV、能量分辨70meV的条件下,基于相对流量技术测量了 N2分子a"∑g+(v'=0)和a"1∑g+(v'=1)+b1Πu(v'=0)的广义振子强度。通过对比电子碰撞的实验结果和最近的X射线散射实验结果,发现对于a"1∑g+(v'=0)和a"1∑g+(v'=1)+b1Πu(v'=0),我们的结果与X射线散射结果在大动量转移出现差异,这表明对a"1∑g+(v'=0)和a"1∑g+(v'=1),即使入射电子能量1500 eV也没有达到一阶玻恩近似条件。在动量转移平方小于2 a.u.时,a"1∑g+(v'=1)+b1Πu(v'=0)与X射线散射结果的符合表明,对b1Πu(v'=0),1500eV入射电子能量已经达到一阶玻恩近似条件;第二部分是基于光吸收方法展开的探索性研究,本论文深入探索了基于Beer-Lambert定则的光吸收实验方法,并详细分析了此实验方法所存在的线饱和效应。随后,为了克服光吸收方法中严重的线饱和效应,我们提出了双荧光法,经过详细的推导表明,原则上这种新的实验方法不受线饱和效应的影响。
[Abstract]:Oscillator strength is a physical quantity describing the transition probability between energy levels, which belongs to the basic parameters of matter at the atomic and molecular level. It is extremely important both theoretically and experimentally. At present, the accuracy of the measurement of this physical quantity in the world is about 10. Our laboratory has long devoted itself to the study of improving the accuracy of oscillator strength measurement. After the laboratory has built a high resolution fast electron energy loss spectrometer completely independently, the relative flow technology has been added. A unified data absolute standard has been established. Recently, based on X-ray scattering technique, a diPole (纬, 纬) method for measuring the optical oscillator strength of atoms and molecules has been proposed for the first time. We have also explored and improved the optical absorption method for measuring the optical oscillator strength. Based on the electron collision method and the optical absorption method, we have measured the oscillator strength of atoms and molecules, and obtained some results. This paper is divided into two parts. The first part is based on the method of electron collision, which includes: the electron energy loss spectrometer is used under the condition that the incident electron energy is 1500 EV and the energy resolution is 70 MEV. Based on the relative flow technique, the generalized oscillator intensities of N _ 2 molecule a "鈭，

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