Influence of quantum statistical weight on efficiency of electric field ionization of atom
文献类型：期刊论文
| 作者 | Dai Chang-Jian1; Qi Xiao-Qiu1,2; Liu Dong-Li1 |
| 刊名 | ACTA PHYSICA SINICA
 |
| 出版日期 | 2017-04-05 |
| 卷号 | 66期号:7 |
| 关键词 | Lithium Atom Three-step Photo-excitation Electric Field Ionization Quantum Statistical Weight |
| DOI | 10.7498/aps.66.073201 |
| 文献子类 | Article |
| 英文摘要 | The quantum statistical weight (G) of an atomic energy level is an important spectroscopic parameter, its effect on the atomic ionization process is, however, usually neglected for simplicity. In this work, the influences of the G parameters of the lithium atomic energy levels are taken into account explicitly for the first time in the study on the process of three-step photo-excitation (PE) + electric field ionization (EFI), which yields a significant effect on overall EFI efficiency of the PE+EFI process. With a set of specially designed PE+EFI schemes, the expected results are obtained. First, with a three-step PE scheme, the Li atom is excited by three pulsed lasers with different wavelengths, which are fired simultaneously, to one of the Rydberg states from its ground state, from which the Li atom is ionized by an electric-field pulse with a time delay in order to avoid the Stark effect. Based on the three physical processes the atom experiences the PE, none field, and the EFI processes, and a set of universal rate equations are established according to the conservation law of particle number with the knowledge of physical mechanism of the three different processes and the physical model set up for them, respectively. The G parameters of the four relevant bound energy states are displayed explicitly in the rate equations for the PE process to offer a clear viewabout their effect on the overall EFI efficiency of the PE+EFI process. Secondly, the overall efficiencies of PE+EFI process are calculated with the Matlab programming for the two specified excitation schemes, 2S(1/2) -> 2P(1/2) -> 3S(1/2) -> 25P(1/2,3/2) and 2S(1/2) -> 2P(3/2) -> 3D(5/2) -> 25F(5/2,7/2). The overall EFI efficiency of PE+EFI process is investigated not only by adjusting the laser parameters but also by comparing the results between the two different excitation schemes. In order to establish the relationship between the overall EFI efficiency and external field quantitatively, the dependence of population rate of the relevant bound states on various factors, such as laser and atomic parameters, is calculated systematically. The role of the G parameters of the relevant atomic energy levels played in the population rates is observed to determine which excitation scheme is better in terms of the population rate of the Rydberg state. Meanwhile, the spontaneous emission of the Rydberg state during the time delay between the pulses of electric field and laser is also evaluated to make a balance between avoiding the Stark effect and minimizing the spontaneous emission. Based on the analysis of the calculations, some new results are achieved. An enhancement of the overall EFI efficiency can be obtained by making a sophisticated design on the excitation scheme of the PE+EFI process to optimize the G parameters. The time delay between the pulses of electric field and laser not only lets the atom experience a field-free time period, but also makes an upper limit for the population rate of Rydberg state due to the redistribution of atom among the four relevant bound states in the period. The upper limit is found to be dependent on neither laser parameters nor the absolute values of the G parameters, while only on the branching ratio of the G parameters among those bound states. |
| WOS研究方向 | Physics |
| 语种 | 英语 |
| WOS记录号 | WOS:000402752100007 |
| 资助机构 | National Natural Science Foundation of China(11174218) ; National Natural Science Foundation of China(11174218) ; National Natural Science Foundation of China(11174218) ; National Natural Science Foundation of China(11174218) |
| 源URL | [http://ir.wipm.ac.cn/handle/112942/11496]  |
| 专题 | 武汉物理与数学研究所_原子分子光物理研究部 |
| 作者单位 | 1.Tianjin Univ Technol, Coll Sci, Tianjin 300384, Peoples R China 2.Chinese Acad Sci, Wuhan Inst Phys & Math, State Key Lab Magnet Resonance & Atom & Mol Phys, Wuhan 430071, Peoples R China |
| 推荐引用方式 GB/T 7714 | Dai Chang-Jian,Qi Xiao-Qiu,Liu Dong-Li. Influence of quantum statistical weight on efficiency of electric field ionization of atom[J]. ACTA PHYSICA SINICA,2017,66(7). |
| APA | Dai Chang-Jian,Qi Xiao-Qiu,&Liu Dong-Li.(2017).Influence of quantum statistical weight on efficiency of electric field ionization of atom.ACTA PHYSICA SINICA,66(7). |
| MLA | Dai Chang-Jian,et al."Influence of quantum statistical weight on efficiency of electric field ionization of atom".ACTA PHYSICA SINICA 66.7(2017). |
入库方式： OAI收割
来源：武汉物理与数学研究所
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