The Pionic Hydrogen Experiment at PSI

The measurement of the strong-interaction effects in pionic hydrogen gives access to fundamental properties of the pion–nucleon interaction. Methods developed within the framework of Heavy-Baryon Chiral Perturbation Theory allow calculations with an accuracy of a few per cent, which should be tested by experiment. Techniques advanced for recent experiments on the precision spectroscopy of X-rays from antiprotonic and pionic atoms will be used in a new series of measurements for pionic hydrogen. The aim is to achieve finally an accuracy of 0.2% for the hadronic shift ∈_1s and most important of about 1% for the broadening Γ_1s . An essential part of the experimental program is an improved understanding of the atomic cascade. At first, the value of ∈_1s has to be proven not to be influenced by molecular formation. Secondly, a more accurate determination of Γ_1s requires a detailed study of Coulomb deexcitation. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Atomic Hydrogen in Two Spatial Dimensions

We resolve the problem of atomic hydrogen in two spatial dimensions exactly. Its spectrum ia different from that in three dimensions, M the angular momentum is not quantised in integer or half of odd-integer. We a h calculate the ground state energies for different cases of the parameter α, which may be related to the statistics of the electron in the atom.     

The Muonic Hydrogen Lamb Shift Experiment at PSI

A measurement of the 2S Lamb shift in muonic hydrogen (μ⁻p) is being prepared at the Paul Scherrer Institute (PSI). The goal of the experiment is to measure the energy difference ΔE(2⁵ P _3/2−2³ S _1/2) by laser spectroscopy (λ≈6μm) to a precision of 30 ppm and to deduce the root mean square (rms) proton charge radius with 10⁻³ relative accuracy, 20 times more precise than presently known. An important prerequisite to this experiment is the availability of long-lived μp_2S -atoms. A 2S-lifetime of ∼1 μs – sufficiently long to perform the laser experiment – at H₂ gas pressures of 1–2 hPa was deduced from recent measurements of the collisional 2S-quenching rate. A new low-energy negative muon beam yields an order of magnitude more muon stops in a small low-density gas volume than a conventional cloud muon beam. A stack of ultra-thin carbon foils is the key element of a fast detector for keV-muons. The development of a 2 keV X-ray detector and a 3-stage laser system providing 0.5 mJ laser pulses at 6 μm is on the way. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Structure and Dynamics of the Chains of Hydrogen Bonds of Hydrogen Fluoride Molecules Inside Carbon Nanotubes

Physics of the Solid State - It is shown by molecular dynamics that hydrogen fluoride molecules inside single-wall carbon nanotubes with a diameter D < 0.85 nm form flat zigzag chains of...     

The Four-Body System Made up of Hydrogen and Antihydrogen

 In view of current interest in the trapping of antihydrogen atoms at low temperatures [1–3], we have investigated the reasons for considering that does not have a bound state. We go on to carry out a four-body variational calculation for s-wave hydrogen-antihydrogen scattering, using the Kohn variational method. This is a continuation of earlier work on interactions [5–7]. Received October 30, 2001; accepted for publication November 21, 2001     

Hydrogen detection by SIMS: Hydrogen on polycrystalline vanadium

The interaction of hydrogen with polycrystalline vanadium has been studied by SIMS and flash-desorption. Two well defined vanadium surfaces with different amounts of residual oxygen were exposed to H₂-doses up to 1000 L. The investigations were carried out under UHV conditions. The experiments result in a better understanding of the vanadium-hydrogen interaction, especially with regard to the influence of residual oxygen. The residual oxygen concentration can be characterized by the O^? emission; it increases with the number of O₂ exposure/ heating cycles. Different groups of secondary ions and flash signals, characteristic of certain chemical environments of hydrogen, could be distinguished. The ratios $\text{VH}{}^{\mathrm{+}}\text{V}{}^{\mathrm{+}}$ and $\text{V}{}_2\text{H}{}^{\mathrm{+}}\text{V}{}^{\mathrm{+}}{}_2$ proved to be typical of the direct V-H bond concentration. This can be derived from their behaviour during H₂ and O₂ exposure, e.g. Bulk dissolved hydrogen is indicated by a dosedepending H₂ flash signal at 900 K. Bulk solution of H₂ is blocked by a monomolecular oxygen layer. An additional H₂ flash signal at 500 K together with increasing values of $\text{VH}{}^{\mathrm{+}}\text{V}{}^{\mathrm{+}}$ and $\text{V}{}_2\text{H}{}^{\mathrm{+}}\text{V}{}^{\mathrm{+}}{}_2$ is observed for relatively oxygen free targets after H₂ exposure. The detection limit for metal-bonded hydrogen was found to be less than 100 ppm of one monolayer.     

Optical Emission of Molecular Hydrogen in a Recombining Hydrogen Plasma

We observed optical emission of molecular hydrogen in a recombining hydrogen plasma with an electron temperature of 0.1 eV and an electron density of 3 × 10¹²cm^–3. The optical emission intensities of molecular hydrogen in the recombining plasma were roughly 10%–45% of those in an ionizing plasma with an electron temperature of 4 eV. The ratio was greater for a transition line originated from an excited state with a larger vibrational quantum number. Because of the low electron temperature of 0.1 eV, the production processes of excited states are not considered electron impact excitation in the recombining plasma. Possible recombination processes are discussed which produce excited states of molecular hydrogen in the recombining plasma (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Hydrogen bond studies

The deuteron magnetic resonance spectra from partially deuterated single crystals of NaHC₂O₄. H₂O have been studied. The quadrupole coupling tensors for stationary deuterons are determined at about 25°C. The quadrupole coupling constants and the assymmetry parameters η of the tensors for the two deuterons in the water molecule are, 235·2 ± 1·9 and 228·5 ± 1·6 kHz, and 0·09 ± 0·01 and 0·13 ± 0·01, respectively. The principal axes corresponding to the largest components both deviate by 0·9 ± 0·5° from their respective O-H directions. For one of the tensors this angular displacement is in the plane of the H₂O molecule and towards the other O-H direction. The displacement for the other tensor is out of the plane of the H₂O molecule.     

多壁碳纳米管储氢的物理吸附特性

采用巨正则蒙特卡罗方法 ,模拟常温、1 0MPa下氢在扶手椅型多壁壁碳纳米管中的物理吸附过程 .氢分子之间、氢分子与碳原子之间的相互作用采用Lennard Jones势能模型 .研究了双壁碳纳米管外 (内 )径固定而内 (外 )径改变时的物理吸附储氢情况 ,发现氢分子主要储存在双壁碳纳米管的管壁附近 ,当双壁碳纳米管的内外管壁间距由 0 .34nm增大到 0 .6 1或 0 .88nm时可有效增加物理吸附储氢量 ,并给出了相应的理论解释 .在此基础上 ,计算了管壁间距为 0 .34、0 .6 1和 0 .88nm时的三壁碳纳米管的物理吸附储氢量 ,并与相同条件下单壁和双壁碳纳米管的物理吸附储氢量作了比较 ,发现多壁碳纳米管的物理吸附储氢量随碳管层数的增加而减小 .     

BC3复合纳米管的储氢性能研究

采用巨正则蒙特卡罗方法（GCMC）研究了BC3复合纳米管的物理吸附储氢性能,获得了该纳米管在不同温度和压强下的吸附等温线,及其在不同条件下的物理储氢吸附量,并和相应的碳纳米管进行了对比研究。结果表明,BC3纳米管在所有条件下的储氢性能均优于相应的碳纳米管,因而它是一种比碳纳米管更强的氢存储介质,并从纳米管和H2分子以及H2分子和H2分子之间的平均总相互作用能的分布情况等因素出发解释了这两种纳米管有不同储氢行为的原因。     

The solution of Hydrogen in TaV2

TaV₂ may be prepared as a random b.c.c. alloy or as a (C-15) Laves phase. The behavior of hydrogen dissolved in b.c.c. TaV₂ is significantly different than that exhibited by hydrogen dissolved in (C-15) TaV₂. The b.c.c. TaV₂/H₂; system is similar to pure vanadium/H₂; in the region of hydrogen solid solution, the electronic contribution to the thermodynamics of solution is negligible and the system exhibits apparent H-H attractive interactions. A non-stoichiometric f.c.c. dihydride is formed at p_H2 = 10 atm, T = 273 K. (C-15) TaV₂ does not form a hydride phase; hydrogen is continuously absorbed into solid solution to a maximum hydrogen content H/M ? 0.60. The solid solution of hydrogen in (C-15) TaV₂ exhibits trends which are typical of intermetallie/H₂ systems. The dilute hydrogen region is marked by a strong positive deviation from Sieverts' Law, and the relative partial molar enthalpy of solution becomes less exothermic as the hydrogen content is increased. ΔV? vs H/M relationships and ΔS_H vs H/M relationships indicate that hydrogen segregation at the metal surface or at abnormally stable trapping sites does not contribute significantly to the thermodynamic behavior exhibited by hydrogen in (C-15) TaV₂. Analysis of the excess free energy of hydrogen suggests that electronic effects may exert a significant influence on the behavior of hydrogen in (C-15) TaV₂, even at dilute hydrogen contents. It is suggested that the radom substitution of tantalum into the vanadium lattice exerts a significantly greater effect on the vibrational entropy of dissolved hydrogen than does the structural transformation b.c.c. TaV₂ → (C-15) TaV₂.     

Hydrogen Release and Room Temperature Creep for Vanadium Alloys Containing Hydrogen

Vanadium alloy has been taken as one of the candidate structural materials for fusion reactors because of its excellent high-temperature mecha nical performances, high thermal stress factor and low radioactivity. It is a kind of potential materials for hydrogen storage as well. Because operated in an environment conta!ning hydrogen and its isotopes or the neutron irradiation resulting transmutation product of H, the problem that H induced degradation of mechanical properties and hydrogen embrittlement has been being one of the key issues for the application for vanadium alloys.     

氢原子电子云的蒙特卡罗模拟

根据量子力学原理,氢原子中电子的几率分布由电子的定态波函数可以唯一地确定.在大多数教科书中,通常是将电子沿径向和角度方向的几率分布分别进行讨论,因此很难给出电子在整个空间几率分布的一个完整图象.我们使用蒙特卡罗随机抽样的方法,通过计算机作图形象而逼真地绘制了氢原子中电子的几率分布图,即所谓的电子云.下面介绍所使用的方法.     

马来酸氢十八酯晶体(OHM)的拉曼光谱研究

为了进一步了解马来酸氢十八酯晶体（ＯＨＭ）的结构,本文测定了ＯＨＭ晶体几何配置为（ｙ（ｚｘ）ｙ）和ｙ（ｘｚ）ｙ和ｙ（ｘｘ）的拉曼光谱。实验表明ＯＨＭ烷烃链的几个振动模式出现偏振,垛;ＯＨＭＳ其他基团的拉曼光谱振动吸收峰也都具应出现。     

High‐Resolution Hydrogen Spectroscopy and The Proton Radius Puzzle

High resolution spectroscopy of the hydrogen atom takes on particular importance in the new SI, as it allows to accurately determine fundamental constants, such as the Rydberg constant and the proton charge radius. Recently, the second most precisely measured transition frequency in hydrogen, $1S?3S$, is obtained by our group. In the context of the Proton Radius Puzzle, this result calls for further investigation.     

生物油制氢中催化剂与吸收剂研究

本文利用固定床反应器考察了自制催化剂在生物油水溶性组分重整制氢反应中的表现以及耦合水蒸气预处理的CO2吸收剂对反应的影响。通过比较自制催化剂与商业催化剂Z417在重整反应中的催化性能,以及预处理吸收剂对重整反应的改进作用,结果表明：在反应温度为800℃,水油比为4．9的条件下,自制催化剂Ni／CeO2-ZrO2的氢产率...     

紧凑型氢等离子体枪设计和实验

 设计了一种紧凑型氢等离子体枪及驱动电路。这种枪采用同轴结构,电极之间有两层石墨环和两层氢化钛,利用氢化钛作为气源储存体,利用表面闪络机制产生等离子体。实验诊断表明,等离子体枪能产生密度为10×¹⁰~10¹²/cm³,半径为1~2cm,长度为60~80cm的等离子体柱,它在磁场导引下存在时间大于400 μs。该枪结构简单、体积小、重量轻、工作电压低、使用方便。适合作为等离子体高功率微波器件中的等离子体源。