氦原子低能态幻零波长与魔幻波长的高精度计算

发布时间：2018-04-23 17:57

本文选题：He原子 + Li~+离子　；参考：《河南师范大学》2016年博士论文

【摘要】：氦原子作为最简单的多电子原子体系,是精密测量物理的重要研究体系,其原子结构的理论计算和跃迁光谱的实验测量在发展多电子原子结构理论、确定基本物理常数和提取原子核信息等方面有重要应用。极化率反映了原子在外场中的响应性质,氦原子的极化率在精密光谱测量中的Ac/Dc斯塔克频移分析中有着重要的应用。在某特定波长的外场下,量子态/量子跃迁感受的Ac斯塔克频移为零时的光波长称为幻零波长/魔幻波长,其在原子冷却囚禁、跃迁矩阵元的精确确定、以及量子电动力学理论检验等方面有着全新的应用。例如,氦原子2 3S态413 nm幻零波长的理论计算和实验测量相结合可以从非能量角度检验量子电动力学(QED)理论;另外,利用氦原子2 1S→23S跃迁的319.8 nm的魔幻波长阱囚禁氦原子,有望提高原子核电荷半径的测量精度。本文自主发展了基于B-样条函数的组态相互作用(CI)计算程序,实现了大规模的并行计算,提高了能级、波函数和跃迁矩阵元的理论预言精度,提供了可靠的极化率、幻零波长和魔幻波长的理论计算结果。具体内容包括:(1)在非相对论框架下,计算了氦原子2 3S、3 3S、2 3P和3 3P态长度、速度和加速度规范下的静电偶极极化率,其中长度和速度规范下极化率的符合程度达到10-7;确定了氦原子一系列处在可见光和红外波段的幻零波长和魔幻波长,其中氦原子2 3S态的413 nm幻零波长B-样条计算结果为413.038 28(3)nm,改善了此前Mitroy和Tang的半经验计算结果,且给出4He、3He情况下该幻零波长的结果分别为413.139 19(2)nm和413.172 22(2)nm;另外我们发现氦原子2 3S→33P跃迁的1066nm魔幻波长可用来确定(2 3S→23P)/(33P→63S)跃迁矩阵元比值,该方法可应用到末态为高激发态的矩阵元测量中。(2)在相对论框架下,采用包含Breit相互作用的CI方法,详细分析了有限核质量效应和相对论效应对氦原子2 3S1态413 nm幻零波长的影响,给出该波长的B-样条理论计算结果为413.085 9(4)nm(MJ=1),将理论计算和实验测量的相对误差减小到19 ppm;同时计算了氦原子双重禁戒跃迁2 1S0→23S1(MJ=1)的一系列可见光波段的魔幻波长,改进了此前的半经验计算,提供了更为可靠的魔幻波长理论预言值。(3)考虑了有限核质量效应和相对论效应对氦原子能级、极化率、魔幻波长和幻零波长的影响后,进一步我们考虑QED修正。首先用B-样条非相对论CI方法计算氦原子能量的QED修正领头项中的贝特对数项(Bethe logarithm),给出了n 3S(n=2-9)态加速度规范下的B-样条计算结果,其中n3S(n=2-5)态贝特对数项的相对不确定度为10-7到10-8。(4)我们将自主发展的基于B-样条函数的组态相互作用计算程序推广到类氦离子体系的计算中,计算了Li+离子2 3S、3 3S、2 3P和3 3P态的极化率,确定了一系列幻零波长和魔幻波长,这些波长大部分处在可见光和紫外波段;同时,我们考虑了有限核质量效应对6Li+和7Li+的能级、振子强度、极化率、幻零波长和魔幻波长的影响。Li+离子幻零波长和魔幻波长的计算为实验上囚禁Li+离子、分析Ac/Dc斯塔克频移提供了可靠的理论输入值。
[Abstract]:As the simplest multi electron atom system, helium atom is an important research system for precision measurement of physics. The theoretical calculation of atomic structure and the experimental measurement of transition spectra have important applications in the development of the theory of multi electron atomic structure, the determination of the basic physical constants and the extraction of nuclear information. The polarizability reflects the atom in the field. The polarizability of the helium atom has an important application in the Ac/Dc frequency shift analysis of the precision spectrometric measurement. Under a specific wavelength, the frequency of the quantum state / quantum transition from the Ac stark frequency shift to zero is called the magic zero wavelength / Magic wavelength, which is accurate in the atom cooling and the transition matrix element. There are new applications in determining the theory of quantum electrodynamics. For example, the theoretical calculation of the 413 nm phantom zero wavelengths of the 2 3S state of helium atom and the experimental measurement can be used to test the theory of quantum electrodynamics (QED) from the non energy angle. In addition, the helium atom is imprisoned by the magic wavelength well of 319.8 nm of the helium atom 2 1S to 23S transition, and the helium atom is imprisoned by the magic wavelength well of the 319.8 nm of the helium atom. It is expected to improve the measurement accuracy of the radius of the nuclear charge. In this paper, the configuration interaction (CI) calculation program based on B- spline function is developed, and a large scale parallel calculation is realized. The theoretical prediction accuracy of the energy level, wave function and transition matrix element is improved, and a theoretical calculation junction of a reliable polarizability, a magic zero wavelength and a magic wavelength is provided. The specific contents include: (1) under the non relativistic framework, the dipolar polarizability of the helium atom 2 3S, 3 3S, 2 3P and 3 3P States is calculated under the specification of the length, velocity and acceleration, in which the coincidence of the polarizability of the length and velocity is up to 10-7, and a series of illusory zero wavelengths and magic in the visible and infrared wavelengths of helium atoms are determined. Wavelengths, in which the 413 nm phantom zero wavelength B- spline of the helium atom 2 3S state is calculated to be 413.03828 (3) nm, improves the previous semi empirical results of Mitroy and Tang, and gives the results of the 4He, 3He under the circumstances of 413.13919 (2) nm and 413.17222 (2) NM respectively. In addition, we find the magic wavelengths of the 2 3S to 33P transition of the helium atom 2 3S. It can be used to determine the ratio of (2 3S to 23P) / (33P to 63S) transition matrix element. This method can be applied to the matrix meta measurement of the high excited state. (2) under the relativistic framework, the effect of the finite nucleus mass effect and the relativistic effect on the illusions of the 413 nm in the 2 3S1 state of the helium atom is analyzed in detail. The effect of the finite nucleus mass effect and the relativistic effect on the 413 nm illusions of the helium atom is analyzed in detail. The theoretical calculation results of B- spline of this wavelength are 413.0859 (4) nm (MJ=1), the relative error of theoretical calculation and experimental measurement is reduced to 19 ppm, and the magic wavelengths of a series of visible light bands of the helium atom double forbidden transition 2 1S0 to 23S1 (MJ=1) are calculated, and the previous semi empirical calculations have been improved and a more reliable magic wavelength theory is provided. 3. (3) considering the effect of the finite nucleus mass effect and the relativistic effect on the helium atomic energy level, the polarizability, the magic wavelength and the illusory zero wavelengths, we further consider the QED correction. First, we use the B- spline non relativistic CI method to calculate the Beit logarithm term (Bethe logarithm) in the QED corrected collar of helium atomic energy, and give the n 3S (n=2). The results of B- spline calculation under -9 state acceleration, in which the relative uncertainty of the n3S (n=2-5) state Bate logarithm term is 10-7 to 10-8. (4), we generalize the self developed configuration interaction calculation program based on B- spline function to the calculation of helium like system, and calculate the polarizability of Li+ ions 2 3S, 3 3S, 2 3P and 3 3P states. A series of illusory zero wavelengths and magic wavelengths, most of which are in visible and ultraviolet wavelengths, and we consider the effects of the finite nuclear mass effect on the levels of 6Li+ and 7Li+, the intensity of the oscillator, the polarizability, the magic zero wavelength and the magic wavelength, and the calculation of the Li+ ion and the magic wavelengths of the.Li+ ions in the experiment, and the analysis of the A C/Dc stark frequency shift provides a reliable theoretical input value.

【学位授予单位】：河南师范大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O562

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