激光场中极化势对电子-氦原子散射影响

构建含有极化势的静电屏蔽势和单纯的静电屏蔽势这两种原子势模型,应用第二玻恩近似（SBA）理论,分别对激光场中电子-氦原子散射截面进行了理论计算。对比实验结果发现含有极化势的静电屏蔽势给出的结果与实验符合较好。表明极化势在激光辅助电子-原子散射中起着重要作用。     

第二玻恩近似理论研究激光辅助e-Ar散射

在电子入射方向平行于激光场的极化方向这种特殊的散射模式下，应用第二玻恩近似(SBA)理论，分别利用含有极化势的静电屏蔽势和单纯的静电屏蔽势这两种原子势模型对激光场中电子-氩原子散射进行了研究，并与低频近似和实验数据进行了比较.结果表明，第二玻恩近似理论给出的结果与实验符合较好.另外，极化势在激光辅助电子-原子散射中起着重要作用. 关键词： 极化势 第二玻恩近似 微分截面 激光场     

激光辅助电子-原子碰撞K-W公式与第二玻恩近似

最近的CO₂激光辅助电子-原子碰撞的测量结果与K-W公式存在着非常大的差异,用玻恩近似理论对此进行了详细的研究.结果表明第二玻恩近似结果与实验结果符合得比较好,K-W公式的预言只相当于第一玻恩近似.同时,计算表明电子-原子间的极化势在激光辅助电子-原子散射过程中起着重要的作用. 关键词：     

相互作用势对激光辅助电子-氩原子散射的影响

在三种势模型下运用二级玻恩近似理论计算了电子与氩原子散射的微分散射截面. 结果显示这些势模型在激光辅助电子-氩原子散射系统中的运用非常成功. 另外,分析和讨论了静电势、交换势和极化势对散射截面的影响.     

激光辅助电子-原子碰撞 K-W公式与第二玻恩近似

最近的 Ｃ Ｏ２ 激光辅助电子原子碰撞的测量结果与 Ｋ Ｗ 公式存在着非常大的差异,用玻恩近似理论对此进行了详细的研究．结果表明第二玻恩近似结果与实验结果符合得比较好, Ｋ Ｗ 公式的预言只相当于第一玻恩近似．同时,计算表明电子原子间的极化势在激光辅助电子原子散射过程中起着重要的作用．     

多模激光场中电子-原子散射

利用微扰理论对多模激光场中电子-原子散射进行了初步研究. 在激光场的极化方向平行于入射电子方向这种特殊的散射模式下, 计算得到了电子-原子微分散射截面与激光场的相移、交换光子数之间的关系. 结论和其它相关理论是一致的.     

离子极化势对钙原子共面对称(e,2e)反应影响的数值研究

本文使用扭曲波波恩近似方法(DWBA)研究了共面对称条件下钙原子的电子碰撞电离反应((e,2e)反应),在DWBA理论的基础上,考虑了原子极化势和离子极化势对三重微分散射截面的影响.采用发展的DWBA方法,我们研究了出射电子能量从6.75 e V到29.25 e V范围内电子与钙原子的碰撞电离过程,计算了电离三重微分截面.通过与已有理论和实验数据进行比较发现,离子极化势对钙原子的共面对称(e,2e)反应散射微分截面有较大的影响,很好的描述了碰撞电离微分截面的结构效应,特别是在散射角度较小时(≦60o),本文计算结果与实验测量非常一致.     

双模激光场中电子-原子散射

在一阶玻恩近似的基础之上,本文首次在激光场的极化方向平行于入射电子的方向这种散射模式下,应用二阶玻恩近似理论对双模激光场中电子-氩原子散射的自由-自由跃迁过程进行了研究,并与一阶玻恩近似结果进行比较.结果表明,二阶玻恩近似理论在多模激光场中的应用也是比较成功的.     

离子极化势对钙原子共面对称(e,2e)反应影响的数值研究

本文使用扭曲波波恩近似方法(DWBA)研究了共面对称条件下钙原子的电子碰撞电离反应( (e,2e)反应 )，在DWBA理论的基础上，考虑了原子极化势和离子极化势对三重微分散射截面的影响。采用发展的DWBA方法，我们研究了出射电子能量从6.75eV到29.25eV范围内电子与钙原子的碰撞电离过程，计算了电离三重微分截面。通过与已有理论和实验数据进行比较发现，离子极化势对钙原子的共面对称(e,2e)反应散射微分截面有较大的影响，很好的描述了碰撞电离微分截面的结构效应，特别是在散射角度较小时(≦60o)，本文计算结果与实验测量非常一致。     

低能正电子与氖,氩原子弹性碰撞截面的理论计算

本文把Khara与Moiseiwitsch极化势推广应用到多电子靶原子散射,并利用等效势模型计算了低能正电子与氖、氩原子弹性碰撞截面,我们的计算结果与别人理论计算及实验都符合的比较好。     

运用球高斯分布极化势研究低能电子与H2 分子碰撞的振动激发动量迁移散射截面

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     

Variable-phase method in positron-hydrogen elastic scattering

The elastic scattering of a positron by a hydrogen atom is studied by using the variable-phase approach to potential scattering. Values of the scattering length and the elastic scattering phase shifts obtained in the (i) static, (ii) polarization and (iii) extended polarization approximations for the e⁺?H interaction are found to be in close agreement with the results of earlier workers.     

Static potential renormalization in time-dependent fields

We consider the scattering of electrons at a static potential under the influence of an additional time-dependent, homogeneous electric field (‘microwave’). Starting from a plane wave basis, we derive a generalization of the Born (first) order approximation in arbitrary strong oscillating fields. As an example, we evaluate the Friedel density oscillations around a static scatterer whose potential is renormalized by the microwave. The microwave leads to a band of inelastic scattering channels with effective potentials, the shape of which can be ‘tuned’ by the microwave polarization and strength.     

高能重离子非对心碰撞中的整体夸克极化

There exists a large local relative orbital angular momentum between produced partons along the direction opposite to the reaction plane in the early stage of non-central heavy-ion collisions. This initial local orbital angular momentum can lead to quark polarization along the same direction due to spin-orbital coupling in QCD. We present the quark polarization by using hard thermal loop gluon propagator for quark-quark scattering in quark-gluon plasma and compare it with the result obtained from the static potential model.     

Out-of-plane spin polarization from in-plane electric and magnetic fields

We show that the joint effect of spin-orbit and magnetic fields leads to a spin polarization perpendicular to the plane of a homogeneous two-dimensional electron system with Rashba spin-orbit coupling and in-plane parallel dc magnetic and electric fields, for angle-dependent impurity scattering or nonparabolic energy spectrum, while only in-plane polarization persists for simplified models. We derive Bloch equations, describing the main features of recent experiments, including the magnetic field dependence of static and dynamic responses.     

Elastic scattering of electrons by argon atoms

The partial wave method with a central potential has been applied to investigate the elastic scattering of electrons by the argon atoms in the intermediate energy range (100 eV − 1 keV). The central potential includes the effects of the static field, exchange and polarization. The results are in good accord with recent experimental data. A brief account of this investigation was presented at the X Int. Conf. on the Physics of Electronic and Atomic Collisions held at Paris in July 1977.     

Scattering of electromagnetic waves by static wormholes

Scattering of electromagnetic waves by static and traversable wormholes is discussed. Based on the fact that these spacetimes have no horizon, and regarding their non-trivial topology, we have developed the perturbation theory of scattering and the Born approximation for obtaining the differential scattering cross section. Some of the zeros of the scattering pattern at long wavelengths are determined which can be used for estimating the radius of the throat. The known result that in scattering by static spacetimes the linear polarization remains unchanged is verified here.