Triple-differential cross section for single ionization of H2 by electron impact

The triple-differential cross section (TDCS) for the (e,2e) ionization of a hydrogen molecule is calculated using the molecule distorted-wave Born approximation (MDWBA). Distorted waves are obtained by solving momentum-space coupled-channel Lippmann-Schwinger equations, including the ground state and the lowest-lying electronic state of b3Σu . TDCSs at the incident energy 100 eV in coplanar asymmetric geometry are reported. The present calculations are compared with the available experimental measurements and the theoretical results.     

反转区电子转移速率的理论研究

利用级联方程方法研究了反转区的电子转移速率与电子态耦合常数以及溶剂弛豫时间的关系.结果表随着电子态间耦合强度的增加,反应速率先增加然后减小,而随着溶剂弛豫时间的减小反应速率增加.我们将这些结果与近似理论费米黄金规则、Landau-Zener公式进行了比较,由于费米金规则基于一阶微扰论,所以只适用于耦合常数较小的情况.而Landau-Zener公式假设电子在跃迁区域弹道运动,在电子态耦合大的情况下也存在问题.     

Unnatural parity resonance states in positron-excited hydrogen scattering

<正>The coupled-channels optical method for positron scattering has been applied to investigate resonance states with unnatural parities in a positron-excited hydrogen system.The positronium formation channels and continuum channel are included via a complex equivalent local potential.Resonance states with angular momenta L = 1 to L = 2 and parities（—1）^L+1 are calculated.Resonance energies and widths are reported and compared with other theoretical calculations.We found that the opening positronium formation channels play an important role in forming nondipole Feshbach resonances.     

Differential cross sections for electron impact excitation of molecular hydrogen using the momentum-space multichannel optical method

In the present work, the momentum-space multichannel optical method is employed in four-state close-coupling calculations to study the electronic excitation of H_2 molecules by electron-impact. Particularly, differential cross sections for the X~1Σ_g~+→ b~3Σ_u~+, X~1Σ_g~+→ aΣ_g~+, and X~1Σ_g~+→ c~3Π_u transitions are reported. Comparison is made with the available experimental and theoretical results.     

Momentum-space calculation of electron-CO elastic collision

We report a momentum-space study on low-energy electron-CO collisions.Elastic differential cross sections(DCS) are obtained using a static-exchange-optical(SEO) model for the incident energies of 2,3,5,and 10 eV.Polarization effect of higher reaction channels,including the ionization continuum,on the elastic collision is represented by an ab initio equivalent-local optical potential.The cross sections are compared with experimental measurements and other theoretical results.     

Elastic and inelastic positron-helium scattering

Elastic and inelastic positron--helium scatterings have been investigated with the coupled-channel optical method (CCO). Ionization continuum and positronium formation channels are included via a complex equivalent-local optical potential. Calculations are reported of cross sections of elastic scattering, total excitation and n=2, 3, and 4 excitations of ground-state helium for incident energies from 30~eV to 400~eV. The present calculation shows that the ionization and Ps-formation channels significantly affect the cross sections of elastic and inelastic positron--helium scatterings.     

Positronium Formation in e^＋-K Collision at Low Energies

Positronium (Ps) formation cross section for positron scattering on potassium is calculated at low impact energies (0.2-15.0eV). The present calculation uses an optical-model method with an equivalent local polarization potential. The results for the Ps (n = 1) and Ps (n = 2) formation cross sections are calculated and compared with the experimental measurements and other theoretical results.     

Coupled-channels optical calculation of positron-hydrogen resonances

An application of the coupled-channels optical method is given for the energy-dependent phenomena of positron-hydrogen resonances below the n=2 excitation threshold.The equivalent local optical potential is used to account for the target polarization and positronium formation.The calculation includes 9 explicitly physical coupled channels.The lowest S-wave resonance energy position and new resonances are found.Angular dependence of the cross section in the resonance region are investigated.     

计算中低能量电子与水分子弹性散射微分截面

运用耦合通道光学势方法计算了在中低能量下的电子与水分子碰撞弹性散射微分截面,其中靶的极化效应被包含在一个从头算的等价局域势中.随后将计算结果与实验值和其它理论计算结果进行了比较.结果显示这种计算方法对于电子与极化分子体系碰撞是非常适用的.     

Resonances in Positron-Mg Scattering

We present the results for resonances in positron-Mg scattering at low impact energy （0-5.0eV） by using the momentum space coupled-channel optical （CCO） method in momentum space. The S-partial wave resonance at 3.880eV, P-partial wave resonance at 4.020eV, and D-partial wave resonance at 4.267eV are found.