Based on the experimental device which is a non-uniform magnetic field to trap an atom, we show how to obtain a certain velocity of a Bose gas by controlling the magnetic coils. By comparing the relationship of the different current supply and delay time versus the ultimate velocity of the atom, we theoretically predict the method of accelerating the gases to an expected velocity. This method is of great convenience and significance for the applications in cold atom physics and precision measurements.
Using the multi-configuration Dirac-Fock self-consistent field method and the relativistic configuration-interaction method, calculations of transition energies, oscillator strengths and rates are performed for the 3s2 1S0-3s3p 1P1 spinallowed transition, 3s2 1S0-3s3p 3P1,2 intercombination and magnetic quadrupole transition in the Mg isoelectronic sequence （Mg I, A1 II, Si III, P IV and S V）. Electron correlations are treated adequately, including intravalence electron correlations. The influence of the Breit interaction on oscillator strengths and transition energies are investigated. Quantum eleetrodynamics corrections are added as corrections. The calculation results are found to be in good agreement with the experimental data and other theoretical calculations.
Scientific research fields for future energies such as inertial confinement fusion researches and astrophysics studies especially with satellite observatories advance into stages of precision physics.The relevant atomic data are not only enormous but also of accuracy according to requirements,especially for both energy levels and the collision data.The fine structure of high excited states of atoms and ions can be measured by precision spectroscopy.Such precision measurements can provide not only knowledge about detailed dynamics of electron-ion interactions but also a bench mark examination of the accuracy of electron-ion collision data,especially incorporating theoretical computations.We illustrate that by using theoretical calculation methods which can treat the bound states and the adjacent continua on equal footing.The precision spectroscopic measurements of excited fine structures can be served as stringent tests of electron-ion collision data.
离化态原子广泛存在于等离子体物质中,其相关性质是天体物理、受控核聚变等前沿科学研究领域的重要基础.基于独立电子近似,本文系统研究了扩展周期表元素(2 Z 119)所有中性和离化态原子的基态电子结构.基于设计的原子轨道竞争图,系统总结了各周期元素轨道竞争的规律,并结合离化态原子的局域自洽势阐明了其轨道竞争(即轨道塌陷)的机制;在此基础上,说明了部分元素性质与轨道竞争的关系.利用本文研究得到的离化态原子基态电子结构,可建立更精密计算相关原子的能级结构、跃迁几率等物理量之基础,从而满足高功率自由电子激光实验分析、原子核质量精密测量等前沿研究的需求.
A laser power feedback control system that features fast response, large-scale performance, low noise, and excellent stability is presented. Some essential points used for optimization are described. Primary optical lattice experiments are given as examples to show the performance of this system. With these performance characteristics, the power control system is useful for applications in cold atom physics and precision measurements.
