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1.
High order Correlation polarization potential for vibrational excitation scattering of diatomic molecules by low-energy electrons 下载免费PDF全文
This paper introduces a correlation--polarization potential
with high order terms for vibrational excitation in
electron--molecule
scattering. The new polarization potential generalizes the two-term
approximation so that it can better reflect the dependence of
correlation and polarization effects on the position coordinate of
the scattering electron. It applies the new potential on the
vibrational excitation scattering from N2 in an energy range
which
includes the 2Пg shape resonance. The good agreement of
theoretical resonant peaks with experiments shows that polarization
potentials with high order terms are important and should be
included in vibrational excitation scattering. 相似文献
2.
用最近改进的球高斯分布(distributed spherical Gaussian,DSG)极化势模型,在振动密耦合框架下和基于量子力学从头计算的静电势、交换势的基础上,研究了低能电子与H2分子碰撞振动激发的动量迁移散射截面(momentum transfer cross section,MTCS).通过包含18个振动波函数、5个分波和16个分子对称性,得到了0<E≤10 eV时收敛性很好的ν=0→ν'=0,1,2,3等几个振动跃迁通道和总的MTCS,并与其他实验和理论得到的值进行了比较和分析.
关键词:
2分子碰撞')" href="#">H2分子碰撞
动量迁移散射截面
振动激发
球高斯分布极化势 相似文献
3.
4.
The differential cross-sections (DCS) of the low-energy electron–N 2 scattering are studied using the vibrational close-coupling (VCC) method and vibrational scattering potentials which include static, exchange and polarization contributions. The polarization is obtained based on the ‘better than adiabatic dipole’ (BTAD) and the ‘distributed spherical Gaussian’ (DSG) respectively. The converged (0 → 0, 0 → 1, 0 → 2, 0 → 3) DCS are obtained with the impact energies being the resonance's first two elastic scattering peaks?–?approximately 1.90 eV and 2.10 eV. Calculations from both polarization potentials agree with experimental results. 相似文献
5.
W. Dai W. G. Sun H. Feng L. Shen 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,39(3):385-389
The vibrational excitation differential cross-sections
(DCS) of low-energy electron-N2
scattering are studied using vibrational close-coupling (VCC) method and
vibrational scattering potentials which include static, exchange and
polarization contributions. By including the contributions of 18 partial
waves, 20 vibrational states, and 16 molecular symmetries (up to Λ=7), the converged vibrational excitation (0↦2, 0↦3, 0↦4)
DCS agree well with experimental results. Also obtained are converged
vibrational (1↦0, 1↦1, 1↦2, 1↦3) DCS, with the impact
energies being those of the main resonant peaks (1.92 eV, 1.90 eV, 1.62 eV,
1.63 eV). 相似文献
6.
严格交换势用于研究低能电子与H2分子的弹性和非弹性散射截面,线性代数方法和R-矩阵传播子相结合求解基于振动密耦合方法的积分-微分耦合方程组,由此得到收敛的(0→0,0→1,0→2)散射微分截面和积分截面.理论计算结果与目前优秀的实验值和其他理论计算值进行了比较,表明基于振动密耦合方程的严格交换势在低能电子与H2分子振动激发散射中有重要作用.
关键词:
严格交换势
2分子振动激发')" href="#">H2分子振动激发
微分截面
积分截面 相似文献
7.
8.
S. Telega F. A. Gianturco 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2006,38(3):495-500
Quantum calculations of the resonant vibrational excitation of N2 by electron impact are carried out using
a model potential for exchange and correlation-polarization forces and exact static interaction. The inelastic process
is treated within a coupled channel, space-frame formulation and final cross-sections are tested for convergence within
less than
of their values. Comparison with the experiments yields very good agreement with the latter data in the resonance region
and suggests
possible extension to calculations near the threshold openings for rovibrational inelastic processes induced by electron impact. 相似文献
9.
Nanosecond scale discharges are considered an interesting way for assisting combustion by enhancing either flame stabilization
or ignition. Better understanding of energy deposit and radical species production processes is still required under pressure
conditions normally encountered in combustion. The purpose of the present paper is to show that spontaneous Raman scattering,
seldom used to investigate nanosecond pulsed discharges, is a useful measurement method for investigating the energy deposit
of these discharges. The advantage of spontaneous Raman scattering is described by analyzing N2 and O2 spectra during the post-discharge of a filamentary nanosecond air discharge under atmospheric pressure, using phase-locked
average spectra. The main advantages of spontaneous Raman scattering measurements are that they allow line-wise probing of
different species with the same experimental setup and the determination of vibrational distribution by comparison with theoretical
modeling over a wide range of vibrational levels (from v=0 to v=20 for N2). The model proposed takes into account the high level of vibrational excitation and the strong non-equilibrium observed,
allowing the characterization of the vibrational relaxation over the complete post-discharge duration. Although the rotational
structure is not resolved, the rotational temperature and thus translational temperature are determined with a moderate uncertainty
for T above 500 K. 相似文献
10.
The effects of the rovibrational excitation of reactants in the N(2D) + D2(X1Σg+) → ND(X3Σ+) + D(2S) reaction are calculated in a collision energy range from the threshold to 1.0 eV using the time-dependent wave packet approach and a second-order split operator. The reaction probability, integral cross-section, differential cross-section and rate constant of the title reaction are calculated. The integral cross-section and rate constant of the initial states v = 0, j = 0, 1, are in good agreement with experimental data available in the literature. The rotational excitation of the D2 molecule has little effect on reaction probability, integral cross-section and the rate constant, but it increased the sideways and forward scattering signals. The vibrational excitation of the D2 molecule reduced the threshold and broke up the forward–backward symmetry of the differential cross-section; it also increased the forward scattering signals. This may be because the vibrational excitation of the D2 molecule reduced the lifetime of the intermediate complex. 相似文献
11.
12.
The correlation-polarization (CP) model-potential, given by O’Connell and Lane (1983) as well as Padial and Norcross (1984)
is examined for the elastic scattering of electrons by oxygen atoms, at intermediate energies. The correlation potential is
found to be stronger than necessary at low energies. Two model polarization potentials based on the CP model, are suggested
and employed to thee
− — O scattering at 8.7, 30, 50 and 100 eV energies. The calculated total cross-sections agree in general with the other data
at these energies. 相似文献
13.
14.
应用全量子的分子轨道强耦合方法,研究了基态的O3+(2s22p 2P)与氢分子碰撞的非解离电荷转移过程,计算了不同方位角(25°,45°,89°),能量分别为100,500,1000和5000eV/u时的单电子俘获的振动分辨的态选择截面及相应的微分截面.分子轨道强耦合计算中采用了自旋耦合价带理论计算的三原子分子势能面和径向耦合矩阵元.对氢分子的自身转动,采用无限阶的冲量近似方法;对体系的电子运动同H2或H+<
关键词:
非解离电荷转移过程
全量子的分子轨道强耦合方法
无限阶冲量近似
振动冲量近似国家自然科学基金(批准号:10604011
10574020)和国家高技术研究发展计划(863)惯性约束聚变领域资助的课题. 相似文献
15.
CARLOS CUNHA RITA PROSMITI PABLO VILLARREAL GERARDO DELGADO-BARRIO 《Molecular physics》2013,111(20):3231-3237
A supermolecular approach is used to predict the stationary structures of the NeBr2(X1Γg +) van der Waals cluster. The intermolecular potential is calculated using the single and double excitation coupled-cluster method with non-iterative perturbation treatment of triple excitations [CCSD(T)]. Relativistic effects are included for the Br atoms using effective core potentials (ECPs) and their efficiency is tested for Br2 and NeBr2 molecules. Our results for NeBr2 show minima for both linear and T-shaped configurations, in accord with previous ab initio calculations for rare gas-Br2 species. The dependence of the interaction potential, as a function of the Br-Br bond, is also presented. Finally, vibrational analysis is carried out to examine the stability of the two isomers including zero-point vibrational energy effects. 相似文献
16.
The differential cross sections for scattering of electrons and positrons from He, Ne, Ar, Kr, and Xe at projectile energies below the inelastic thresholds are calculated using a model potential approach in which the interaction between the projectile and the target atom is partitioned into static, exchange (for electrons), and correlation-polarization parts. Two different forms of the parameter-free correlation-polarization potential are suggested; in both cases the correlation-polarization potential is determined by smoothly matching the asymptotic form of the polarization potential (1/r
4) to the correlation potential at the outermost orbital radius of the target atom. The results of angular distributions are presented in the form of contours of constant differential cross sections as well as in the form of differential cross section surfaces in three-dimensional plots. Both of these presentations display the locations of the principal maxima and minima of the differential cross sections as well as the critical points in a very useful manner. 相似文献
17.
Experimental and theoretical investigations of the optical conductivity of K2Pt (CN)4Br0,3 · 3H2O single crystals for phonon energies near the plasma edge are reported. The imaginary part of the dielectric function is determined by only two scattering processes: Elastic scattering of holes by the Coulomb potentials of randomly distributed Br-ions and inelastic scattering by excitation of plasmons. 相似文献
18.
I. Kuusik T. Käämbre K. Kooser V. Pustovarov V. Ivanov E. Kukk A. Kikas 《Journal of Electron Spectroscopy and Related Phenomena》2011,184(7):366-370
Resonant X-ray inelastic scattering spectra have been measured in BeO, phenakite (Be2SiO4) and chrysoberyl (BeAl2O4) with the excitation energy near the beryllium K edge.The RIXS spectra excited in the vicinity of the Be 1s core resonance show two principal features: the scattering on a valence excitation (which at higher excitation energies verges into the characteristic Kα emission), and a remarkably strong energy loss sideband to the elastic scattering peak. The energy loss shoulder appears to result from lattice relaxation in the absorption site. The comparison of the RIXS spectra of phenakite, chrysoberyl and BeO shows that the strength of the low energy sideband differs greatly; it is strongest in BeO and weakest in phenakite. The Si 2p RIXS spectra of phenakite also display a similar strong sub-bandgap energy loss tail.To gain further insight to this process, transitions in a system with a single vibrational mode have been modelled. The phonon relaxation has been simulated empirically by “smearing” the photoabsortion-populated vibrational levels with lower levels. This simple model is able to qualitatively explain this wide energy loss shoulder. 相似文献
19.
Vibrationally elastic total cross-sections ofe
−—H2O scattering are calculated at intermediate energiesE
i=10–300 eV. The interaction potentials are treated in spherical models. The dipole rotational excitation, which is significant
but not dominant above 10 eV, is treated incoherently. Effects of electronic excitation-ionization, significant above 30 eV
or so, are considered through a complex optical potential. A dynamically distorted charge-density is employed to calculate
the imaginary part of the complex potential. Comparisons are made with recent theoretical and experimental data. The mutual
agreement is better in total cross-sections than in differential cross-sections. 相似文献
20.
State-resolved measurements are presented for vibrational excitation of H2, N2, O2 and CO2 by H? impact in the collision energy rangeE cm=20–180 eV and for scattering in the forward direction (0±0.5°). The data obtained from the measurements are the relative intensities and differential cross sections for vibrational excitation up toν′=4, the transition probabilitiesP 0→ν′ and the vibrational energy transferΔE vib. For the systems H?-H2, N2, O2 the vibrational inelasticity increases in the order H2-N2-O2. The mechanism for vibrational excitation in these systems is due to transient charge transfer from the H? ion into antibonding orbitals of the target molecule which provides a bond stretching force during the collision. For H2 and N2, the results are compared with corresponding measurements for H+ scattering where the interaction mechanism is quite different. In the case of CO2, vibrational excitation in forward scattering is caused primarily by the long-range dipole interaction. The spectra are very similar for H?-CO2 and H+-CO2. Finer details are attributed to the influence of transient charge transfer and valence interactions. 相似文献