UV spectroscopy of charge exchange collisions between N5+ ions and H2, He

We report results concerning a spectroscopic study of radiative transitions observed during the collision between N⁵⁺ ions with H₂ and He. Excitation cross section and their energy variation are measured. In addition to the simple electron capture, strong double electron capture is shown with the He target.     

Populations of np terms in deuterium atoms emergent from carbon foils bombarded with D+, D2+ and D3+ ions

We have measured relative beam-foil populations of 2p, 3p, and 4p terms in D⁰ as a function of the projectile energy $\text{(20 ?}\text{E}\text{M}\text{? 500}\text{keV}\text{amu}\text{)}$ for D⁺, D₂⁺, and D₃⁺ ions impinging on carbon foils of various thicknesses (? 2–20 $\text{μg}\text{cm}{}^2$).With D⁺ projectiles, the np populations reach their equilibrium values even in the thinnest foils used. We compare the dependence on energy of these populations to the equilibrium neutral fraction variation for hydrogen (deuterium) beams emerging from a carbon foil and deduce some information concerning beam-foil populations.When molecular projectiles pass through very thin foils, well known molecular effects appear which depend on the dwell time, t, i.e., the time spent by the projectile in the foil. In this work we consider only the long-dwell-time region t > 2 × 10^?15s. We study the variation of R_α = I^molec/I^atom (I^molec and I^atom are the Ly-α intensities per incident deuteron (proton) observed with molecular and atomic projectiles of the same velocity, respectively) with the projectile energy per nucleon ($\text{E}\text{M}$) and the thickness (T) of the foil. For a foil of given thickness, R_α increases with $\text{E}\text{M>}$ and reaches a saturation value R_∞ which decreases when T increases. These results, in agreement with our previous measurements using hydrogen projectiles, indicate that t is not the only parameter relevant to molecular effects. Comparisons are reported between $\text{R>}{}_{\mathrm{\alpha }}\text{(E}\text{M>}$) values obtained (a) with H₂⁺ and D₂⁺ projectiles and (b) with D₂⁺ and D₃⁺ projectiles, using foils of various given thicknesses. Ratios $\text{R}{}_{\mathrm{\beta }}\text{(E}\text{M}$) and $\text{R}{}_{\mathrm{\gamma }}\text{(E}\text{M}$) are also measured using Ly-β and Ly-γ radiations and compared to $\text{R}{}_{\mathrm{\alpha }}\text{(E}\text{M}$) values. An interpretation for some of our results is proposed.     

Beam-foil spectroscopical study of the 1s2s2p and 1s2p2 quartet levels of Mg9+ and Al10+

Results of recent measurements of the fine structure and multiplet separation of the lowest quartet terms of doubly excited three-electron ions of Mg and Al are compared with other experiments and with theory. Preliminary results of lifetime measurements of 1s2p²⁴P_1/2.3/2 levels are presented. They confirm the recent calculation by Chen. Crasemann and Mark and contradict older calculations by Tunnell and Bhalla.     

(n,l)−Subshell electron capture cross sections in collisions of C4+, N5+ and O6+ with atomic hydrogen

By means of VUV-photon spectroscopy we have determined absolute Subshell selective electron capture cross sections σ_nlfor collisions of helium-like carbon, nitrogen and oxygen ions with atomic hydrogen, in the velocity range 0.1–0.5 a.u.The atomic hydrogen beam target was produced by means of a radio-frequency discharge source, and absolutely calibrated by measuring atomic and molecular radiation in the visible region produced by electron impacts.For all systems studied we find that the total capture cross section (σ_t = Σ_nlσ_nl depends only weakly on the impact velocity, and is in good agreement with published results from other authors. In contrast to σ_t, the Subshell selective cross sections σ_nl are strongly velocity dependent.Our results are compared with recent calculations by Fritsch and Lin; the agreement is quite satisfactory.     

He+ (np) cross sections for 2, 3, 4 and 5 MeV C4+ ions colliding with He atoms

The cross sections of ionization plus excitation of He are measured by the C⁴⁺ + He prototype reaction with energies ranging from 2 to 5 MeV. Theoretically the independent electron approximation is used to calculate the HeII (np) ionization plus excitation cross sections. The results of the calculations are compared with our experimental data.     

二硫代氨基甲酸盐树脂的合成及其对废水中Fe3+、Co2+、Mn2+的吸附性能研究

以D309树脂为原料,采用甲醇 水溶液法合成二硫代氨基甲酸盐（DTCR）树脂,利用红外光谱和扫描电镜对其结构进行了表征,测试了合成树脂对废水中Fe³⁺、Co²⁺、Mn²⁺的吸附性能,并通过等温吸附实验和动力学实验考察了合成树脂对金属离子的吸附去除能力随接触时间的变化情况和吸附机理。研究表明,该树脂对Fe³⁺、Co²⁺、Mn²⁺的吸附符合Langmuir等温线,在25 ℃下最大吸附量可分别达25.07、20.58、41.87 mg/g,吸附速率较快,吸附4 h均可达到吸附平衡;在二元金属离子混合体系中,树脂对3种金属离子的吸附关系遵守Mn²⁺＞Co²⁺＞Fe³⁺的基本关系;Ca²⁺、Mg²⁺干扰离子存在情况下,树脂对Co²⁺的去除率基本不变,维持在97%左右,树脂对Fe³⁺的去除率得到提高,由50%上升到98%,而树脂对Mn²⁺的去除率反而下降,由92%下降到80%。     

Sputtering of materials by H+, D+, T+ and He+ Ions

The sputtering yields of various materials by H⁺, D⁺, T⁺, He⁺ ions were calculated using the theoretical dependence of sputtering yields on energy and ion mass and taking into account experimental sputtering yield values, whenever available, as measured for H⁺, D⁺, T⁺, He⁺ ions.     

电动势法研究HAN与Fe3+氧化还原反应动力学

采用电动势法研究了硝酸体系中硝酸羟胺(HAN)还原Fe3+离子的反应动力学,得到了动力学表观速率方程-dc(Fe3+)/dt=kc0.62(HAN)c-2.80(H+)c(Fe3+)c-0.85(Fe2+);当温度为50℃、离子强度I=1.0mol/L时,表观速率常数k=(2.9±0.1)×10-6(mol/L)3.02/s,反应表观活化能Ea=(125±3)kJ/mol。硝酸根的存在对反应起到抑制作用,离子强度的增大对反应有促进作用。     

LiErO2 formation on Er2O3 in static and natural convection lithium

Er₂O₃ is candidate material for insulating coating to prevent the magnetohydrodynamic (MHD) pressure drop in the self-cooled liquid Li blanket system. Although Er₂O₃ is stable material, detailed chemical behavior in liquid Li is not clear. Corrosion behavior of bulk Er₂O₃ in Li is investigated in static and flowing condition in the present study. After these tests, good compatibility of Er₂O₃ was confirmed and slight formation of LiErO₂ was detected by XRD analysis. This chemical behavior did not change in a static and flowing tests, however some of the corrosion product of LiErO₂ was removed easily by the Li flow. Intensity of LiErO₂ peaks in XRD spectrum suggests that the temperature gradient may affect the reaction rate in the natural convection loop. Since corrosion rate of Er₂O₃ is very small, slight change in state will be important information to evaluate lifetime of coating.     

Wavelengths and classifications of emission lines due to 2s22pn−2s2pn + 1 and 2s2pn−2pn + 1 transitions, Z ≤ 28

Tables of wavelengths and classifications of observed emission lines due to 2s²2pⁿ?2s2p^{n + 1} and 2s2pⁿ?2p^{n + 1} transitions are presented. The accuracy of data derived from different experimental methods is discussed. Revised and predicted wavelengths are added. Energy levels are derived from the wavelength data.     

The (p, n) reaction in lithium and the ground state of Be6

Using a time-of-flight method the neutron spectra in the Li⁶ + + p and Li⁷ + p reactions have been investigated at a proton energy of 9 Mev. Neutron groups have been found in the (p, n) reaction corresponding to the ground state in Be⁶ and the three lowest states of Be⁷ as well as a continuous neutron spectrum at lower energy, due to more complicated reactions. The observation of the neutron group for the Li⁶(p, n)Be⁶ reaction is the first experimental indication of the existence of the Be⁶ nucleus. The energy of the Li⁶(p, n)Be⁶ reaction is 5.2 Mev, the width of the ground state in Be⁶ is T < 0.3 Mev. The differential cross sections for neutron formation have been measured at 0, 15, 30, 60 and 120 °.The authors wish to thank their colleagues at the Cyclotron Laboratory, who made the present work possible; we are also indebted to A. I. Baz who participated in a discussion of the results.     

XAFS study of Cu2+ in aqueous solution of CuBr2

Copper ion is the essential microelement to many organisms. In this paper, the local structure of Cu2+ in CuBr2 aqueous solutions with different concentrations are investigated by using X-ray absorption fine structure (XAFS) technique. XANES (X-ray Absorption Near Edge Structure) spectra indicate that charge transfer from Br- to Cu2+ decreases with the solution concentration, which lead to a shift of the absorption edge. The shoulder appearing at the rising edge proves to be characteristic of a tetragonal distortion. The Fourier transform magnitudes of EXAFS (Extended X-ray absorption fine structure) data of Cu species suggest that more Cu-Br bonds may exist in high concentrations. A fivefold coordination configuration like a pyramid is used as the fitting parameters. From the analysis of the coordination numbers, the proportion of Cu-O and Cu-Br is 4:1 in the saturated solution. The Br atom is on the equatorial plane of the model. The fitting results agree well with the experiment data.     

纳米球状碳酸钙对水中铀酰离子的吸附

在添加剂聚苯乙烯磺酸钠(PSS)作用下合成了纳米球状CaCO3,并使用扫描电镜(SEM)对其形貌进行表征。通过静态批实验的方法研究了pH值、离子强度、温度等因素对铀酰离子在纳米球状CaCO3上吸附的影响。结果表明:铀酰离子的吸附率随体系pH的增大而升高,随体系离子强度的增大而降低;温度增加时,纳米球状CaCO3对铀酰离子的平衡吸附量明显增加。热力学研究表明,UO22+在纳米球状CaCO3上的吸附反应是吸热自发进行的。     

Single electron capture in slow He2+-Li collisions

Optical measurements of single electron capture in He²⁺ -Li collisions are reported in the energy range 0.55–10keV/amu. These low energies were inaccessible in our earlier work on the same system [1].Cross sections for emission of the 1s?np (n = 2, 3, 4) Lyman series of He II have been measured with a VUV grazing incidence spectrometer. From these we have deduced the total capture cross section σ_t, and the subshell-selective capture cross sections σ_3p and σ_4p.Correction factors connected with the polarisation of the emitted radiation were applied to our data, using theoretical results of Fritsch and Lin [2], who calculated capture cross sections for nlm?states.Our results for σ_t, are in excellent agreement with very recent charge state selection measurements by Varghese et al. [3]. Both the total and the partial cross sections agree very well with theoretical results by Fritsch and Lin [2]. Comparison with other experimental and theoretical results is also made.     

Phase changes of the ZrO2-12wt%Y2O3 film with Ar+ irradiation

The zirconia containing 12wt%Y₂O₃ thin films deposited by r.f. magnetron sputtering at 25℃ or 400℃, and then bombarded with Ar⁺ beam at room temperature were characterized with XRD before and after Ar⁺ bombardment. It is found that a series of phases formation and transformation happened, among them the mostimportant event is that T' phase appeared after Ar⁺ irradiation andthe content of the T' phase increased with the increase of Ar⁺ iondoses from 5×10¹⁵ to 6×10¹⁶ ions cm^-2.     

The internal conversion coefficients of the 2+–0+, E2 nuclear transitions in even-even nuclei

Measured values of the internal conversion coefficients of 39 E2 (2⁺–0⁺) transitions in even-even nuclei are listed and averaged in most of the cases where there is more than one result. Comparison with values calculated without interpolation by Band, Listengarten, and Trzhaskovskaya shows only fair agreement but no consistent clustering above or below the theoretical expectations. In 13 out of the 39 cases the experimental error bar does not include the theoretical value. Of the experimental values 21 are greater and 18 less than the calculated results.     

Double electron capture by protons in collisions with H2

Double electron capture of protons in collisions with molecular hydrogen in the energy range 1.5-10 keV was studied by measuring the resulting H^- velocity distributions. In this paper, a technique that provides experimental evidence about double capture mechanisms is proposed. In addition, cross-sections for this process were measured in the energy range of 1-5 keV.     

Formation of Na24 and P32 in the interaction of high-energy protons with compound nuclei

The variation of the yields of Na²⁴ and P³² nuclei from copper, lanthanum, gold, and thorium with the proton energy has been studied by a radiochemical method. The curves show that the yields of these nuclei increase considerably with increase of the proton energy from 120 to 660 mev. It was found that the yields of Na²⁴ and P³² nuclei depend to a considerable extent on the atomic number of the target element. A comparison of the calculated formation thresholds of Na²⁴ and P³² nuclei in spallation and fission reactions with experimental estimates of these thresholds led to the conclusion. that they are formed by strongly asymmetric fission of copper, lanthanum, and gold nuclei. An exception is P³², which is formed from copper as the result of a spallation reaction. This last process plays a significant role in the formation of Na²⁴ from copper.     

Formation of Na24 and P32 in the interaction of high-energy protons with compound nuclei

The variation of the yields of Na²¹ and P³² nuclei from copper, lanthanum, gold, and thorium with the proton energy has been studied by a radiochemical method. The curves show that the yields of these nuclei increase considerably with increase of the proton energy from 120 to 660 mev. It was found that the yields of Na²⁴ and P³² nuclei depend to a considerable extent on the atomic number of the target element. A comparison of the calculated formation thresholds of Na²⁴ and P³² nuclei in spallation and fission reactions with experimental estimates of these thresholds led to the conclusion that they are formed by strongly asymmetric fission of copper, lanthanum, and gold nuclei. An exception is p³², which is formed from copper as the result of a spoliation reaction. This last process plays a significant role in the formation of Na²⁴ from copper.