重元素原子，离子禁戒跃迁研究及基于EBIT的等离子体分解研究

【作者】 刘永；

【导师】 邹亚明；

【作者基本信息】 复旦大学 ， 原子与分子物理， 2008， 博士

【摘要】 禁戒跃迁广泛地存在于各种天体,实验室等离子体中.禁戒跃迁在等离子体电子温度,电子密度诊断方面有着重要的应用.本工作利用基于MulticonfigurationDirac-Fock（MCDF）方法的grasp VU程序包,系统研究了一系列重元素原子,离子的禁戒跃迁.具体内容包括以下几个方面:一.系统研究了类锌等电子系列第一激发态4s4p ^1,3P 4条能级的激发能,及它们到基态及它们之间各跃迁的跃迁几率.重点研究了自旋禁戒跃迁4s^{2 1}S₀-4s4p ³P₁和超精细诱导跃迁4s^{2 1}S₀-4s4p ³P₀.能级的结果指出了目前存在的实验之一对类锌Zr¹⁰⁺,Mo¹²⁺及Rh¹⁵⁺的能级³P₂或者³P₀的确定有误.首次给出了类锌等电子系的超精细诱导跃迁4s²-4s4p ³P₀的跃迁几率.该部分主要内容发表在Journal of Physics B,目前该文已被引用7次.二.系统研究了类铑等电子系列基态谱项分裂[Kr]4d^{9 2}D_3/2,5/2,同时计算了能级²D_3/2的寿命.本工作关于类铑等电子系列基态谱项分裂的结果和实验值的相对差别在0.1%的水平,关于Xe X谱项分裂的结果指出了其它理论计算值和实验值不符合的原因.基于这一理论计算,我们同时测量了类铑钡离子的基态谱项分裂,实验值和本文理论计算值相差约为4（?）（0.1%）.理论计算结果目前已经整理成文.三.细致研究了锶（Sr）原子第一激发态5s5p ^1,3P 4条能级的激发能,及它们到基态及它们之间各跃迁的跃迁几率.研究的重点是能级5s5p ³P₂的寿命,由于目前存在的理论值（1048 s）和实验值(520_-140⁺³⁰¹ s)差别很大.本工作的结果（1071s）和此前的理论值符合的很好.考虑到长寿命能级测量的困难,目前实验值和理论值的差别可能主要来自于实验.该部分主要内容发表在Physical Review A.四.细致研究了锘（No）原子第一激发态7s7p ^1,3P 4条能级的激发能,目的是指导即将开展的超重元素能级测量.本工作的计算结果支持目前存在的两组理论值之一,它们之间的差别高达10%.该部分主要内容发表在Physical ReviewA.以上是本博士论文的工作重点,本博士论文另外一部分是基于EBIT（Electron Beam Ion Trap）的实验研究.EBIT是一种用于产生高电荷态离子的小型加速器装置,目前使用该装置已经产生了U⁹²⁺.这一装置集离子源和光源于一体,被约束在装置中的高电荷态离子与电子发生着各种过程,例如:激发,退激,电离,复合等.我们可以通过研究各种原子过程辐射出的光子来研究原子结构信息.另外,产生的高电荷态离子也可以被引出与其它粒子束或固体表面相互作用.我们利用上海EBIT测量了类氢和裸氪离子的辐射复合过程,通过对辐射复合过程辐射出光子计数率的研究得到了一定条件下上海EBIT中类氢和裸氪离子的数密度.文章发表在Journal of Physics:Conference Series.另外,我们还在东京CoBIT（Compact EBIT）上测量了类铑钡离子的基态谱项分裂.更多还原

【Abstract】 Forbidden lines are very useful in plasma diagnostics,such as the determination of the electron density and temperature.We did some research on forbidden lines of heavy elements,and they are as follows:Ⅰ.We presented a systematic calculation along the zinc-like sequence.The excitation energies for the 4s4p ^1,3p levels,and the transition probabilities for the transitions within the 4s4p ^1,3p levels and between these levels and the ground state,are given.Our focus is on the spin-forbidden line 4s^{2 1}S₀ - 4s4p ³P₁ and the hyperfine induced transition（HPF） 4s^{2 1}S₀ - 4s4p ³P₀.Our results for the excitation energies,pointed out the possible misidentification of the ³P₂ or ³p₀ levels in Zr¹⁰⁺,Mo¹²⁺ and Rh¹⁵⁺.Plus,we presented the transition probability for the HPF transition along the zinc-like ions for the first time.This work was published in Journal of Physics B.Ⅱ.A systematic calculation was performed for the ground term splitting [Kr]4d^{9 2}D_3/2,5/2 and the lifetime of the ²D_3/2 level along the rhodium-like sequence. The difference between our calculated results and available experimental values is on the level of 0.1%,and the calculated result for Xe X explained the discrepancy between the previous calculated value and the experimental value.Based on this work,I proposed the experiment on the direct measurement of the ground term splitting for the Rh-like Ba,which has been performed in Tokoyo CoBIT （Compact EBIT） by Professor Zhang Xuemei.The paper about the theoretical work was prepared already.Ⅲ.We performed a large scale calculation on the excitation energy of the 5s5p ^1,3p levels in Sr I.The transition probabilities for the transitions within the 4s4p ^1,3p levels and between these levels and the ground state,are given as well. Our focus is on the lifetime of the ³P₂ level,of which the lifetime difference between the previous calculated value and experimental one is very huge.Our calculated value supports the theoretical one rather than the experimental one.This work was published in Physical Review A.Ⅳ.A large scale calculation on the excitation energy of the 7s7p ^1,3p levels in No I was performed,to guide the forthcoming experiment.Our calculated result supports one of the previous two theoretical results,and the different between them is around 10%.This work was published in Physical Review A.The above is the main part of this thesis,and the other part is about two experiments performed on EBIT（Electron Beam Ion Trap）.EBIT is a combination of the light source and the ion source,in which the produced highly charged ion are trapped.Many atomic processes occur inside EBIT,and one can do spectroscopy research based on the emission photons among the atomic processes.Besides,one can extract the highly charged ions to do kind of surface collision experiment.One experiment is on the radiative recombination measurement for bare and hydrogen-like Kr.This experiment was performed on Shanghai EBIT,and the result was used to estimate the ion density inside Shanghai EBIT.This work was published in Journal of Physics:Conference Series.The other experiment is on the direct measurement of the ground term splitting for the Rh-like Ba.This experiment was performed on the Tokoyo CoBIT （Compact EBIT）.更多还原