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1.
Structure and dynamics of highly charged heavy ions studied with the electron beam ion trap in Tokyo
Nobuyuki Nakamura Zhimin Hu Hirofumi Watanabe Yueming Li Daiji Kato Fred J. Currell Xiao-Min Tong Tsutomu Watanabe Shunsuke Ohtani 《Hyperfine Interactions》2011,199(1-3):123-130
In this paper, we present the structure and the dynamics of highly charged heavy ions studied through dielectronic recombination (DR) observations performed with the Tokyo electron beam ion trap. By measuring the energy dependence of the ion abundance ratio in the trap at equilibrium, we have observed DR processes for open shell systems very clearly. Remarkable relativistic effects due to the generalized Breit interaction have been clearly shown in DR for highly charged heavy ions. We also present the first result for the coincidence measurement of two photons emitted from a single DR event. 相似文献
2.
Andreas Wolf Henrik Buhr Manfred Grieser Robert von Hahn Michael Lestinsky Eva Lindroth Dmitry A. Orlov Stefan Schippers Ioan F. Schneider 《Hyperfine Interactions》2006,172(1-3):111-124
Stored fast ion beams in atomic and molecular collision experiments are discussed with an emphasis on electron–ion interactions
at low relative energies. Recent progress was obtained in electron collision spectroscopy using an electron-cooled stored
ion beam and a separate electron target in the same storage ring; from a cryogenic photocathode, electron beams with internal
temperatures of 5 to 10 K were produced. Results are presented for dielectronic recombination resonances, resolving the hyperfine
structure of stored lithiumlike scandium ions and obtaining precise results for the fine structure splitting of these ions,
and for ro-vibrational resonances in the recombination of electrons with hydrogen molecular ions, revealing sharp structures
down to 2 meV. An overview of the cryogenic storage ring (CSR) project in Heidelberg is given. 相似文献
3.
Enhancement of electron–ion recombination rates at low energy range in the heavy ion storage ring CSRm 下载免费PDF全文
Nadir Khan 黄忠魁 汶伟强 汪书兴 汪寒冰 马万路 朱小龙 赵冬梅 冒立军 李杰 马晓明 汤梅堂 殷达钰 杨维青 杨建成 原有进 朱林繁 马新文 《中国物理 B》2020,(3):169-175
Recombination of Ar14+, Ar15+, Ca16+, and Ni19+ ions with electrons has been investigated at low energy range based on the merged-beam method at the main cooler storage ring CSRm in the Institute of Modern Physics, Lanzhou,China. For each ion, the absolute recombination rate coefficients have been measured with electron–ion collision energies from 0 meV to 1000 meV which include the radiative recombination(RR) and also dielectronic recombination(DR)processes. In order to interpret the measured results, RR cross sections were obtained from a modified version of the semiclassical Bethe and Salpeter formula for hydrogenic ions. DR cross sections were calculated by a relativistic configuration interaction method using the flexible atomic code(FAC) and AUTOSTRUCTURE code in this energy range. The calculated RR + DR rate coefficients show a good agreement with the measured value at the collision energy above 100 meV.However, large discrepancies have been found at low energy range especially below 10 meV, and the experimental results show a strong enhancement relative to the theoretical RR rate coefficients. For the electron–ion collision energy below 1 meV, it was found that the experimentally observed recombination rates are higher than the theoretically predicted and fitted rates by a factor of 1.5 to 3.9. The strong dependence of RR rate coefficient enhancement on the charge state of the ions has been found with the scaling rule of q3.0, reproducing the low-energy recombination enhancement effects found in other previous experiments. 相似文献
4.
The population of metastable states of singly and doubly charged rare-gas ions created by electron capture in keV ion-atom collisions is investigated by means of a subsequent electron stripping or capture collision. 相似文献
5.
N. V. Novikov 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2011,5(2):279-283
The calculations of the cross section for single-electron capture by fast ions are carried out in the Oppenheimer-Brinkman-Kramers
approximation. The dependences of the experimental and calculated cross sections for single-electron capture by fast singly
charged ions on the collision energy coincide. This makes it possible to estimate the cross section for electron capture in
the case of ion-atom collisions if experimental data are absent. The results of calculations for projectiles with filled s-type subshells show that the contribution of electron capture channels to the excited state of the scattered particle depends
on the collision energy. 相似文献
6.
Here we review and discuss some of our recent investigations on collective excitation in a free C60 molecule and its influence on the atomic collisions. In particular, emphasis has been given for collisions with fast highly
charged ions. It is demonstrated, from the charge-state-dependence studies of recoil-ion spectra, that the plasmon excitation
plays a dominant role in the single and double ionization process. The observed linear charge-state-dependence is in contrast
to the expected behavior predicted by ion-atom collisions models. This behavior was observed for different projectiles and
at different energies. The time-of-flight recoil-ion mass spectroscopy experiments involve 1–5 MeV/u C, O, F and Si ion beams
with different charge states, ranging between 4+ and 14+. In addition, the influence of the collective excitation on the electron capture process was also investigated. The wake-field
induced Stark-mixing and splitting of sub-levels of projectile-ions following electron capture from C60 carries signature
of the collective plasmon excitation. For the electron capture studies X-ray spectroscopic technique was used for collisions
with bare and dressed S and Cl ion beams. The results on the TOF data on fullerene target obtained in last few years will
be summarized. 相似文献
7.
Ajay Kumar D. Misra A. H. Kelkar U. R. Kadhane K. V. Thulasiram Lokesh C. Tribedi 《Pramana》2007,68(6):983-994
We have studied fast ion-atom and electron-atom collision processes using a reconditioned high resolution X-ray spectrometer.
The X-rays, generated by the collisions, are dispersed by a curved ADP crystal (Johansson geometry) and detected by a gas
proportional counter. A self-written LabVIEW based program has been used to give precise and controlled movement to the crystal
and for data acquisition. The performance was tested by detecting the Kα diagram and satellite lines of several elements.
The Kα satellite lines of Al have been studied in collision with 3–12 keV electrons and 40 MeV C4+ ions. In ion collisions as large as four L-vacancies are created simultaneously with the K-vacancy, compared to two satellites
in case of the e-impact. In addition, we have measured the X-rays from H-, He- and Li-like Si ions which arise due to the
electron loss/capture process in highly charged 80 MeV Si7+ ions in collision with thin carbon foil. Approximate charge state distribution has been obtained using this new technique.
相似文献
8.
The KLL dielectronic recombination processes for highly charged krypton, iodine and barium ions 下载免费PDF全文
The KLL dielectronic recombination (DR) processes of
ions from highly charged helium-like to oxygen-like krypton, iodine
and barium ions are studied systematically in the relativistic
distorted-wave approximation with configuration interaction. The KLL
DR resonant energies, the corresponding resonant strengths and the
theoretical spectra for each highly charged ion species are
obtained. The results accord well with other available values. The
behaviour of KLL resonant strengths for He-like ions with atomic
number Z is analysed. 相似文献
9.
The KLL dielectronic recombination processes of highly charged He-like to C-like Kr ions have been studied experimentally. The measurement was performed on the newly developed Shanghai electron beam ion trap (Shanghai-EBIT) facility. Characteristic x-rays from both dielectronic recombination and radiative recombination are detected as the electron beam energy is scanned through the resonances. The KLL resonant strengths obtained are 5.41×10^-19, 4.33×10^-19, 3.59×10^-19, 2.05×10^-19 and 0.98×10^-19 cm^2 eV for He-like to C-like Kr ions, respectively. 相似文献
10.
The KLn dielectronic recombination processes of trapped highly charged B-like through He-like Cu ions are studied theoretically, and the theoretical results are used to analyse our previous experimental data at Heidelberg electron beam ion trap (EBIT). The theoretical resonant positions agree with the experimental resonant positions to a precision of 0.4%, in comparison with the resonant positions of those highest peaks between theory and experiment. The experimental spectra are then fitted using a formula with the theoretical resonant energies and strengths, the result shows good overall agreement between theory and experiment over a wide electron energy range. The distribution of highly charged states is obtained from the fitting parameters. 相似文献
11.
T. Kühl 《Hyperfine Interactions》1993,78(1-4):221-230
Heavy ion cooler rings have been installed in a number of laboratories around the world. They allow for a new generation of experiments using the products of high energy heavy ion collisions, i.e. highly charged andpossibly radioactive ions. The first series of investigations at the SIS-ESR facility at the GSI, reviewed here, includes the observation of beta decay into a bound state of a highly charged ion andprecision spectroscopy of inner-shell levels by means of X-ray spectroscopy, laser spectroscopy andresonant di-electronic recombination. 相似文献
12.
J. Davis V.L. Jacobs P.C. Kepple M. Blaha 《Journal of Quantitative Spectroscopy & Radiative Transfer》1977,17(2):139-147
Calculations are presented for the rates of radiative energy loss from tokamak plasmas arising from radiation processes involving collisions between electrons and multiply-charged Fe impurity ions. The distribution of ionization states is determined from the steady-state corona model. The inclusion of dielectronic recombination raises the temperature at which each ion has its maximum equilibrium abundance. For certain nonhydrogenic ions, the dielectronic recombination rates obtained from previous calculations are found to be overestimated due to the neglect of autoionization into an excited state of the recombining ion. Electron impact excitation of resonance line radiation in the far ultraviolet and X-ray regions is the dominant radiative cooling mechanism at temperatures where ions with bound electrons are abundant. However, the radiation emitted during dielectronic recombination can be more important than direct recombination radiation and bremsstrahlung. 相似文献
13.
《Comptes Rendus Physique》2002,3(3):353-364
We review progress made in understanding Coulomb explosion of multiply charged atomic clusters. Their collision with highly charged atomic ions leads to clusters in charge states as high as z=10 with little vibrational excess energy; these systems approach the Rayleigh limit. Phase transitions become evident at higher excess energies. Numerous studies have been devoted to Cz+60, like collisions with surfaces, multi-coincidence fragmentation analysis and gas-phase reactions. Stability and decay of highly charged micrometer-sized droplets and of metal di- and trianions have been monitored in ion traps. Excitation by femtosecond laser pulses allows to unravel properties of highly charged transient cluster ions. To cite this article: O. Echt et al., C. R. Physique 3 (2002) 353–364. 相似文献
14.
光致电离等离子体在宇宙中广泛存在于强辐射场附近. 近年来随着高能量密度实验装置的发展, 在实验室内也能构造出光致电离等离子体. RCF是一个基于The Flexible Atomic Code 数据的针对光致电离等离子体的辐射碰撞模型, 该模型模拟了两个光致电离实验, 其 理论结果中电离态分布和光谱与测量值符合得很好. 在理论模拟中发现, 光致电离等离子体中光致激发和碰撞激发过程对离子态布居和发射光谱都有非常重要的影响. 光致激发过程可以通过将离子激发到双激发态从而间接电离离子; 碰撞激发过程会因为电子将基态离子激发到电离截面小的单激发态而抑制光子对等离子体的电离. 光致激发过程可以加强类锂离子的类氦离子的卫线, 而碰撞激发过程会影响类氦离子谱线的线强之比. 相似文献
15.
A. Müller T. Bartsch C. Brandau A. Hoffknecht H. Knopp S. Schippers O. Uwira J. Linkemann A.A. Saghiri M. Schmitt D. Schwalm A. Wolf F. Bosch B. Franzke C. Kozhuharov P.H. Mokler F. Nolden M. Steck T. Stöhlker T. Winkler H. Danared D.R. DeWitt H. Gao H. Lebius R. Schuch W. Spies W. Zong G.H. Dunn W.G. Graham J.A. Tanis J. Doerfert D. Savin Z. Stachura 《Hyperfine Interactions》1998,114(1-4):229-235
New recombination experiments with merged cold beams of electrons and atomic ions have been carried out at the storage ring
facilities TSR in Heidelberg, ESR in Darmstadt, and CRYRING in Stockholm. A brief overview is given on the recent activities
in which the Giessen group was engaged. Topics of this research were dielectronic recombination (DR) of astrophysically relevant
ions, recombination of highly charged ions with respect to cooling losses in storage rings, field effects on DR, search for
interference effects in photorecombination of ions, correlation effects in DR of low-Z ions, spectroscopy of high-Z ions by DR, and lifetimes of metastable states deduced from DR experiments.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
16.
V. Bernigaud B. Manil L. Maunoury J. Rangama B. A. Huber 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(1):125-130
Ionisation and ion-induced fragmentation of tetraphenyl iron (III) porphyrin chloride (FeTPPCl) molecules have been studied
after slow collisions (v∼ 0.2 a.u.) with multiply charged ions (O3+, Ar8+). Intact molecules and large fragments are observed in charge states up to q=4. For q=1, the intact molecule is the most
abundant species, in particular, when projectiles in higher charge states are used. When the internal energy of the singly
charged ion is increased by the energy transfer during the collision, the singly charged system de-excites by the emission
of a neutral Cl-atom, a free electron or possibly a negative Cl anion. The processes are observed as direct as well as delayed
processes on a μs-time scale. For q=2 to 4 the loss of the Cl-atom and some phenyl groups becomes more likely due to the lower
stability and the larger energy transfer. The charge state distribution of atomic fragments is found to be very different,
in particular, when Cq+ and Clq+ ions are compared. In the first case mainly singly charged ions are detected, whereas in the second case ions in charge states
up to q=6 are observed with high intensities. These phenomena are discussed in terms of the intramolecular charge mobility. 相似文献
17.
X-ray emission spectra for L-shell of Li-like aluminium ions are simulated by using the flexible atomic code based on the collisional radiative model. Atomic processes including radiative recombination, dielectronic recombination, collisional ionization and resonance excitation from the neighbouring ion (Al^9+ and Al^11+ ) charge states of the target ion (Al^10+) are considered in the model. In addition, the contributions of different atomic processes to the x-ray spectrum are analysed. The results show that dielectronic recombination, radiative recombination, collisional ionization and resonance excitation, other than direct collisional excitation, are very important processes. 相似文献
18.
González Martínez AJ López-Urrutia JR Braun J Brenner G Bruhns H Lapierre A Mironov V Soria Orts R Tawara H Trinczek M Ullrich J Scofield JH 《Physical review letters》2005,94(20):203201
We present experimental data on the state-selective quantum interference between different pathways of photorecombination, namely, radiative and dielectronic recombination, in the KLL resonances of highly charged mercury ions. The interference, observed for well resolved electronic states in the Heidelberg electron beam ion trap, manifests itself in the asymmetry of line shapes, characterized by "Fano factors," which have been determined with unprecedented precision, as well as their excitation energies, for several strong dielectronic resonances. 相似文献
19.
The model of collisions of ions with gas atoms, considering resonant charge exchange of ions, polarization and elastic (gas-kinetic)
interactions is constructed. Ion drift characteristics in the dc electric field are calculated. The results are compared to
calculations based on the Bhatnagar-Gross-Krook model collision integral (BGK integral). It is shown that the use of the BGK
collision integral leads to significant errors due to the specificity of ion-atom collisions. 相似文献
20.
双电子复合是一种共振辐射复合过程,在这一过程中,一个具有特定能量的自由电子与电离度为q的离子A~(+q)碰撞,形成有两个电子激发的自电离态n_(?)l_(?)nl,该自电离态进一步发射光子,复合成A~(+(q-1))离子,一系列n(?)l_(?)nl自电离态(n_(?)l_(?)l固定,n从有限到无限变化)形成一个通道,本文在相对论单组态理论基础上,具体探讨了类氦铁离子(3s_(1/2)~nP_(1/2))J=(?)通道中,双电子复合速率随n的变化规律,根据本文得到的规律,可以很方便地计算任意离子的任意一
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