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1.
Cross section for electron impact ionization of carboplatin, C6H12N2O4Pt, and oxaliplatin, C8H14N2O4Pt, have been calculated within binary-encounter-Bethe model for energies from the ionization threshold up to 5000 eV. Cross section for elastic electron scattering from carboplatin and oxaliplatin molecules have also been derived using independent atom method (IAM) and additivity rule for collision energies ranging from 50 eV to 3000 eV. Obtained cross sections have been compared with relevant cross sections for cisplatin molecules. 相似文献
2.
Thana Maihom Ivan Sukuba Ratko Janev Kurt Becker Tilmann Märk Alexander Kaiser Jumras Limtrakul Jan Urban Pavel Mach Michael Probst 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2013,67(1):1-5
We report calculated electron impact ionization cross sections (EICSs) for beryllium (Be) and some of its hydrides from the ionization threshold to 1 keV using the Deutsch-Märk (DM) and the Binary-Encounter-Bethe (BEB) formalisms. The positions of the maxima of the DM and BEB cross sections are very close in each case while the DM cross section values at the maxima are consistently higher. Our calculations for Be are in qualitative agreement with results from earlier calculations (convergent close-coupling, R matrix, distorted-wave and plane-wave Born approximation) in the low energy region. For the various beryllium hydrides, we know of no other available data. The maximum cross section values for the various compounds range from 4.0 × 10?16 to 9.4 × 10?16 cm2 at energies of 44 to 56 eV for the DM cross sections and 3.0 × 10?16 to 5.4 × 10?16 cm2 at energies of 40.5 to 60 eV for the BEB cross sections. 相似文献
3.
J. P. Santos F. Parente 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,47(3):339-350
Total ionization cross sections of neutral phosphorus, arsenic,
antimony, and bismuth atoms by electron impact are reported and
compared to the only available experimental results by Freund et al. [Phys. Rev. A 41, 3575 (1990)]. These calculations take into account the possibilities that some
target atoms used in the experiments were in metastable states close
to the ground state, the excitation-autoionization of nsnp4
excited states may be substantial, and the ions produced in
experiments may be in excited, low-lying metastable states. The cross sections for direct ionization calculations are based
on
the BEB model by Kim and Rudd [Phys. Rev. A 50, 3954 (1994)].
Plane-wave Born cross sections scaled by the method developed by Kim
[Phys. Rev. A 64, 3954 032713 (2001)] are used to determine the
contributions from excitation-autoionization. The combination of the BEB model and the scaled Born cross sections
is in agreement with the experimental data by Freund et al. These theoretical data are useful to experimentalists and can
be
used to complete data tables needed for plasma or astrophysical
studies. 相似文献
4.
The modified Jain–Khare semi-empirical formalism for the evaluation of differential and integral electron impact ionization cross sections for molecules has been extended to the evaluation of cross sections for the electron ionization of CO2 clusters: (CO2)240 and (CO2)1700. The energy dependent differential cross sections are evaluated at the incident electron energies of 50, 100 and 200 eV. The integral total ionization cross sections have been calculated in the energy range varying from ionization thresholds to 1000 eV which revealed a good agreement with the available experimental and the theoretical data. The ionization rate coefficients have also been evaluated using the presently calculated ionization cross sections and Maxwell–Boltzmann energy distributions. 相似文献
5.
Stefan E. Huber Daniel Süß Michael Probst Andreas Mauracher 《Molecular physics》2019,117(17):2233-2240
ABSTRACTWe report total electron-impact ionisation cross sections (EICSs) of cisplatin, its hydrolysis products and transplatin in the energy range from threshold to 10?keV using the binary-encounter-Bethe (BEB) and its relativistic variant (RBEB), and the Deutsch-Märk (DM) methods. We find reasonable agreement between all three methods, and we also note that the RBEB and the BEB methods yield very similar (almost identical) results in the considered energy range. For cisplatin, the resulting EICSs yield cross section maxima of 22.09?×?10?20?m2 at 55.4?eV for the DM method and 18.67?×?10?20?m2 at 79.2?eV for the (R)BEB method(s). The EICSs of monoaquated cisplatin yield maxima of 12.54?×?10?20?m2 at 82.8?eV for the DM method and of 9.74?×?10?20?m2 at 106?eV for the (R)BEB method(s), diaquated cisplatin yields maxima of 7.56?×?10?20?m2 at 118.5?eV for the DM method and of 5.77?×?10?20?m2 at 136?eV for the (R)BEB method(s). Molecular geometry does not affect the resulting EICS significantly, which is also reflected in very similar EICSs of the cis- and trans-isomer. Limitations of the work as well as desirable future directions in the research area are discussed. 相似文献
6.
T. Kirchner H. Tawara I. Yu. Tolstikhina A. D. Ulantsev V. P. Shevelko Th. Stoehlker 《Technical Physics》2006,51(9):1127-1136
Multielectron ionization of neutral atoms by fast positive ions is considered in terms of the independent particle model. A relatively simple technique for calculating the multielectron ionization probabilities and cross sections through the impact parameter is suggested in which one-electron ionization probabilities are represented as normalized exponentials p nl(b) = p nl(b) = p nl(0)exp(?αnl b), where b is the impact parameter and n and l are quantum numbers of the target atomic shell. Exponent αnl is determined from the Born one-electron ionization cross section for target atoms, and preexponential p nl(0) (the ionization probability at a zero impact parameter) is found from a geometrical model. This technique provides the normalization condition p nl(b) ≤ 1 irrespective of the velocity and charge of striking ions and makes it possible to calculate the one-, two-, and three-electron ionization cross sections, which, when added up, make a major contribution to the total cross section, up to a factor of 2. The results of our computations are compared with experimental data and analytical results of other authors. 相似文献
7.
D. Bochicchio R. Ferrando 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2012,66(5):1-7
Theoretical studies of electron impact double ionization cross sections of Ne5+ and Ne6+ ions have been performed in the binary encounter approximation (BEA). Direct double ionization (DDI) has been investigated in the modified double binary encounter model. The K-shell ionization cross sections have been also calculated in the BEA to take into account the contributions to double ionization from the ionization-autoionization (IA) process. The effect of the Coulombic field of the target ion on the incident electron has been considered in the present work. Accurate expression of σ ΔE (cross section for energy transfer ΔE) and the Hartree-Fock (HF) velocity distributions for the target electrons have been used throughout the calculations. The present results are in overall moderate agreement with the experimental observations. Possible reasons behind the discrepancies between the theory and the experiment have been discussed. 相似文献
8.
M. Vinodkumar K. Korot P. C. Vinodkumar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,59(3):379-387
In this article, we report calculations of total
ionization cross sections, Q
ion
, for simple atoms (C, N, O, F) and
molecules (NO and NH3)_{3}) of atmospheric interest on electron impact at
energies from threshold to 2000 eV. We have employed the complex scattering
potential – ionization contribution (CSP-ic) method for the present study.
Attempt has been made to improve the method by computing the parameter that
involves the ratio of sum of the total excitation cross sections
(Σ
Q
exc
) and total inelastic cross section (Q
inel
) at the peak of the
inelastic cross section. The present study not only provided a better
estimation of the parameter involved in the CSP-ic method but also provided
better agreement with the available experimental and theoretical data on the
ionization cross sections of the simple atomic and molecular targets studied
here. 相似文献
9.
在考虑分子内原子间的几何屏蔽效应随电子入射能量变化的基础上, 提出了一种能够在中、高能区准确计算“电子-分子”散射总截面的可加性规则修正方法. 利用这一修正后的可加性规则并使用“电子-C, H, O, N原子”散射总截面的实验数据, 在50—5000 eV内计算了电子被NO, N2O, NO2和C2H6分子散射的总截面, 且将计算结果与实验结果及其他理论结果进行了比较. 结果表明, 利用这一方法修正过的可加性规则进行计
关键词:
电子散射
可加性规则
总截面
几何屏蔽效应 相似文献
10.
The production of target atomK-shell X-rays has been studied for 2 to 28 MeV fluorine ions incident on thin solid targets of 14 elements with atomic numbers Z2=22 to 57. Total X-ray production cross sections, energy shifts ofK α andK β lines andK α/K β intensity ratios were measured with a Si(Li) detector. The results of cross section measurements are compared with theoretical predictions of inner shell ionization. In most cases, satisfactory agreement between measured cross sections and theoretical Coulomb ionization cross sections, corrected for the perturbation of the target atom by the projectile charge and for relativistic effects, was obtained. 相似文献
11.
S.U. Haq Ali Nadeem M. Nawaz 《Journal of Quantitative Spectroscopy & Radiative Transfer》2012,113(16):2058-2065
The absolute photoionization cross sections from the 6p 2P1/2 excited state of cesium at threshold and above the threshold region have been measured using the saturation absorption technique. The photoionization cross section at the ionization threshold is determined as 22.6±3.6 Mb, whereas in the region above threshold its value ranges from 22 to 20 Mb for photoelectron energies up to 0.1 eV. A comparison of the photoionization cross sections with earlier reported theoretical and experimental data have been presented and are in good agreement within the uncertainty. In addition, the oscillator strengths of the 6p 2P1/2→n d 2D3/2 (21≤n≤60) Rydberg transitions of cesium have been calibrated using the threshold value of the photoionization cross section. A complete picture of the oscillator strengths from the present work and previously reported data from n=5–60 is presented. 相似文献
12.
S.H. Simon P.L. Gonthier R.K. Choudhury M.N. Namboodiri K. Hagel S. Kniffen R. Patton L. Adler J.B. Natowitz 《Nuclear Physics A》1984,430(1):249-268
Energy spectra, angular distributions, and elemental yield distributions have been measured for products Z = 1?9 produced in the reactions of 12C on 12C. A total reaction cross section 1170?100+170 mb was determined from the measured elemental cross sections and the principle of charge conservation. This total reaction cross section is about 250 mb less than the geometric cross section and agrees with the Glauber-model calculations of DeVries and Peng. The experimental energy spectra, angular distributions, and yield distributions were compared with those from model calculations for the statistical decay of the products of fusion and of incomplete fusion reactions. For both types of calculations, a modified version of the code LILITA was used. By comparing the data to model calculations, an upper limit of 75 mb for the fusion cross section was determined. That limit corresponds to an upper limit of Lcrit for fusion of 10? in the sharp-cutoff approximation. The dominant reaction mechanisms appear to be incomplete fusion processes. 相似文献
13.
Dr. Minakshi L. K. Jha S. N. Chatterjee B. N. Roy 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2009,51(3):331-339
H+ and He2+ impact single and double ionization cross
sections of ground state lead atoms have been calculated in the binary
encounter approximation. Calculations of direct double ionization cross
sections have been performed in the modified double binary encounter model.
The accurate expressions of σΔE (cross-section for energy
transfer ΔE) and Hartree-Fock velocity distributions for the target
electrons have been used throughout the calculations. Contributions to
double ionization from Auger effect following ionization of inner shells
have been considered in the present work. Our H+ impact single and
double ionization cross sections are in good agreement with the experimental
observations. In calculations of He2+ impact cross sections, the
present theoretical approach shows limited success in the experimentally
investigated region (50–350 keV amu-1). 相似文献
14.
The spin exchange and chemi-ionization cross sections have been calculated for the metastable helium atom-potassium atom system in the ground state. The data on the spin exchange cross section in the system He(23 S 1)-K(42 S 1/2) have been obtained for the first time. The cross sections were calculated for the collision energies ranging from 2 × 10?4 to 60 × 10?4 au The chemi-ionization cross sections obtained have been compared with the data in the literature. 相似文献
15.
Chetan Limbachiya Minaxi Vinodkumar Mohit Swadia K.N. Joshipura Nigel Mason 《Molecular physics》2013,111(1):55-62
We report total inelastic, total ionisation and summed total excitation cross sections for electron scattering on furan, tetrahydrofuran (THF) and 2,5-dimethylfuran at energies between the ionisation threshold and 5 keV. We have employed the spherical complex optical potential formalism (SCOP) to calculate the total inelastic cross sections (Qinel) and have used complex scattering potential-ionisation contribution (CSP-ic) method to derive total ionisation cross sections (Qion) and summed total excitation cross sections (∑Qexc) from the calculated Qinel. We have also computed Qion for these molecules using binary-encounter-Bethe (BEB) approach. We have compared our total cross sections (TCS) with available experimental as well as previous theoretical results and have found good agreement. The results are presented graphically as well as numerically. 相似文献
16.
Avi Marchewka Er’el Granot 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2014,68(9):1-7
The photo-absorption cross sections for the dissociative ionization and dissociative excitation of H 2 + are calculated for photon polarization parallel and perpendicular to the internuclear axis. The wavefunctions for the initial and final states are prepared using the Born-Oppenheimer approximation. For dissociative ionization, the cross section and angular distribution of photo-electrons are compared with those calculated with the fixed-nuclei approximation. For dissociative excitation, the cross sections for H?(N = 1~4) productions are shown. 相似文献
17.
We have measured the absolute values of the total cross section of the one-electron capture by He2+ ions in the kinetic energy range 2–30 keV at the Ar atoms. The absolute values of the differential scattering cross sections of He+ ions formed during the one-electron capture and the electron capture with ionization at energies of 2.2, 5.4, and 30 keV have been determined. The electronic states of the formed ions have been determined using collision spectroscopy based on analysis of the change in the kinetic energy of He+ after the interaction. We have measured doubly differential (with respect to the kinetic energy and the scattering angle) cross sections of the formation of free electrons. The free electron formation channels (direct ionization and electron capture with ionization) have been analyzed by calculating the electron terms of the (HeAr)2+ system. The calculated cross section of capture with ionization is in conformity with the cross section measured using collision spectroscopy. 相似文献
18.
J. Mahoney V. Tarnovsky K. H. Becker 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2008,46(2):289-293
We measured absolute partial cross sections for the formation of all singly
charged positive ions produced by electron impact on SiCl2 and SiCl
from threshold to 200 eV using the fast-neutral-beam technique. Some of the
cross section curves exhibit an unusual energy dependence with a pronounced
low-energy maximum at an energy around 30 eV, which may be indicative of the
presence of indirect ionization channels. Dissociative ionization channels
are dominant for both species. The experimentally determined total single
ionization cross sections for both species agree very well with calculated
cross sections using the Deutsch-M?rk (DM) formalism. A brief summary of
the ionization cross sections determined for all four SiClx (x=1–4)
species is given highlighting similarities and differences. 相似文献
19.
K-shell ionization cross section measurements are reported for35Br,37Rb and39Y targets caused by protons over 300–400 keV energy range in 20 keV increment. The K-shell ionization cross sections (σ
k
l
) at different energies were deduced from the Kα and Kβ X-ray production cross sections which were obtained from X-ray yields of the Kα and Kβ transitions. The experimental values are compared with the calculated values of ECPSSR theory and empirical reference cross
sections. The resultant K-shell ionization cross sections are found to be in reasonable agreement with the ECPSSR theory.
The Kα/Kβ intensity ratios are also presented and compared with other experimental values and also with the theoretical one-hole values
given by Scofield. 相似文献
20.
The triple differential cross sections for the ionization of helium from its ground state 11S and metastable states 21S and 23S in coplanar asymmetric geometry by 150, 250 and 400 eV electrons have been calculated in the BBK model. The present results are compared with the experimental data and/or the other theoretical ones. It has been found that the structures for the metastable states differ markedly from those for the ground state. The collision mechanisms for the new structures appearing in the cross sections for the ionization from metastable states have been analysed. And it has been shown how the intensity of recoil peak changes due to the size of the electron orbital. In addition, the optimal kinematical situations for the cross sections are explored for future experiment. 相似文献