Calculation of Radiative Corrections to E1 matrix elements in the Neutral Alkalis

Radiative rates of transitions from the 2s2p$^{3}$ $^{5}$S°$_{2}$ level of neutral carbon

The measured radiative rates of the 2s22p2 3P1,2 - 2s2p3 5S°2 intercombination transitions in neutral carbon reported in the literature are critically evaluated by comparing them with theoretical and semi-empirical results. The experimental and theoretical values are compared for the carbon isoelectronic sequence from neutral carbon to nine-times ionized phosphorous. We find strong support for the currently recommended theoretical data on C I and conclude that the published measurements for this transition in neutral carbon cannot be trusted. The reasons for the discrepancies are not clear, an…

Light-assisted ion-neutral reactive processes in the cold regime: radiative molecule formation vs. charge exchange

We present a combined experimental and theoretical study of cold reactive collisions between laser-cooled Ca+ ions and Rb atoms in an ion-atom hybrid trap. We observe rich chemical dynamics which are interpreted in terms of non-adiabatic and radiative charge exchange as well as radiative molecule formation using high-level electronic structure calculations. We study the role of light-assisted processes and show that the efficiency of the dominant chemical pathways is considerably enhanced in excited reaction channels. Our results illustrate the importance of radiative and non-radiative process…

中性铥辐射特性的理论与实验比较

Comparison of theory and experiment for radiative characteristics in neutral thulium

本研究通过傅里叶变换光谱测量中性铥发射谱线强度，并结合组态相互作用与多体微扰理论计算，验证其跃迁概率、朗德g因子、超精细结构常数及电四极矩。

中性镉中的多极跃迁振幅与辐射衰变速率

Multipole transition amplitudes and radiative decay rates in neutral cadmium

该研究针对中性镉的禁戒电子跃迁，推导多极跃迁矩阵元解析表达式，结合组态相互作用与多体微扰理论计算多类跃迁贡献，得到激发态寿命等参数，验证了模拟精度，为镉相关精密光谱与冷碰撞研究提供基准。

Ion-neutral chemistry at ultralow energies: Dynamics of reactive collisions between laser-cooled Ca^+ ions and Rb atoms in an ion-atom hybrid trap

Cold chemical reactions between laser-cooled Ca^+ ions and Rb atoms were studied in an ion-atom hybrid trap. Reaction rate constants were determined in the range of collision energies <E_{coll}>/k_B = 20 mK-20 K. The lowest energies were achieved in experiments using single localized Ca^+ ions. Product branching ratios were studied using resonant-excitation mass spectrometry. The dynamics of the reactive processes in this system (non-radiative and radiative charge transfer as well as radiative association leading to the formation of CaRb^+ molecular ions) have been analyzed using high-level qu…

The radiative potential method for calculations of QED radiative corrections to energy levels and electromagnetic amplitudes in many-electron atoms

We derive an approximate expression for a "radiative potential" which can be used to calculate QED strong Coulomb field radiative corrections to energies and electric dipole (E1) transition amplitudes in many-electron atoms with an accuracy of a few percent. The expectation value of the radiative potential gives radiative corrections to the energies. Radiative corrections to E1 amplitudes can be expressed in terms of the radiative potential and its energy derivative (the low-energy theorem): the relative magnitude of the radiative potential contribution is ~alpha^3 Z^2 ln(1/(alpha^2 Z^2)), whi…