Pressure Shifts in High-Precision Hydrogen Spectroscopy: II. Impact Approximation and Monte-Carlo Simulations
A. Matveev, N. Kolachevsky, C. M. Adhikari, U. D. Jentschura
备注：
26 pages; 2 figures; this is part 2 of a series of two papers; part 1 carries article number 075005, while part 2 carries article number 075006 in the journal (online journal version has been rectified)
We investigate collisional shifts of spectral lines involving excited hydrogenic states, where van der Waals coefficients have recently been shown to have large numerical values when expressed in atomic units. Particular emphasis is laid on the recent hydrogen 2S-4P experiment (and an ongoing 2S-6P experiment) in Garching, but numerical input data are provided for other transitions (e.g., involving S states), as well. We show that the frequency shifts can be described, to sufficient accuracy, in the impact approximation. The pressure related effects were separated into two parts, (i) related to collisions of atoms inside of the beam, and (ii) related to collisions of the atoms in the atomic beam with the residual background gas. The latter contains both atomic as well as molecular hydrogen. The dominant effect of intra-beam collisions is evaluated by a Monte-Carlo simulation, taking the geometry of the experimental apparatus into account. While, in the Garching experiment, the collisional shift is on the order of 10 Hz, and thus negligible, it can decisively depend on the experimental conditions. We present input data which can be used in order to describe the effect for other transitions of current and planned experimental interest.
The compression property of hydrogen at megabar pressures and the form of the repulsive interaction potential in hydrogen at short distances
结果表明，氢原子之间的相互作用势的排斥部分的斜率高于解离极限随着减少核间的分离。这种形式的排斥势解释了最近实验中得到的兆巴压力下氢同位素激波和准等熵压缩曲线斜率的减小[R. F. Trunin，V.D. Urlin和A. B. Medvedev，Phys.-美国\textbf{53}，577（2010），R. I. Ilkaev，\textit{et al.}，AIP Conf. Proc. \textbf{706}，73（2004）]。
Superatomic hydrogen: achieving effective aggregation of hydrogen atoms at pressures lower than that of metallic hydrogen
Institute of Atomic and Molecular Physics, Jilin University（吉林大学原子与分子物理研究所）；Key Laboratory of Material Simulation Methods & Software of Ministry of Education, College of Physics, Jilin University（吉林大学物理学院教育部材料模拟方法与技术重点实验室）；Institute of Theoretical Chemistry, College of Chemistry, Jilin University（吉林大学化学学院理论化学研究所）
Finite-nuclear-size effect for hydrogenlike ions under high external pressure
College of Physics, Jilin University（吉林大学物理学院）；Institute of Theoretical Physics, Chinese Academy of Sciences（中国科学院理论物理研究所）；Institute of Applied Physics and Computational Mathematics（应用物理与计算数学研究所）；Department of Nuclear Engineering and Management, Graduate School of Engineering, The University of Tokyo（东京大学工学研究科核工程与管理系）；Department of Physics, Graduate School of Science, The University of Tokyo（东京大学理学研究科物理系）；RIKEN Center for Interdisciplinary Theoretical and Mathematical Sciences (iTHEMS)（理化学研究所跨学科理论与数学科学中心）
