1KeV电子入射单电离氦原子三重微分散射截面的理论研究
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摘要
用3C模型、DS3C模型对1KeV电子入射氦原子(e,2e)反应中的三重微分散射截面进行了计算,并将理论计算结果与实验数据进行了比较,研究了各种屏蔽效应对散射平面内以及垂直平面内三重微分散射截面的影响,并对三重微分散射截面变化规律进行了探讨.结果表明:各种屏蔽效应对散射平面内三重微分散射截面的贡献可以忽略;而在垂直平面内,这些效应对三重微分散射截面结构存在较强影响;另外,末态出射电子与靶核的相互作用直接影响散射平面内和垂直平面内截面的结构及其变化规律.
Under the condition of 1 KeV incident energy,by making use of 3C model and DS3C model,the triple differential cross sections of electron-impact single ionization of the ground state of helium are calculated. The results are compared with those of corresponding experiments to systematically make a research on the influence of various screening effects on the triple differential cross section in the scattering plane and the perpendicular plane. The change tendency of triple differential cross section is analysed. It is shown that the influences of final channel screening effect and distorting effect on the triple differential cross sections in the scattering plane can be ignored. The influence of these effects on the triple differential cross sections in the perpendicular plane is stronger. In addition,the contributions of interreaction between outgoing electrons and nucleus to the change tendency of differential cross sections in the scattering plane and perpendicular plane are stronger.
Under the condition of 1 KeV incident energy,by making use of 3C model and DS3C model,the triple differential cross sections of electron-impact single ionization of the ground state of helium are calculated. The results are compared with those of corresponding experiments to systematically make a research on the influence of various screening effects on the triple differential cross section in the scattering plane and the perpendicular plane. The change tendency of triple differential cross section is analysed. It is shown that the influences of final channel screening effect and distorting effect on the triple differential cross sections in the scattering plane can be ignored. The influence of these effects on the triple differential cross sections in the perpendicular plane is stronger. In addition,the contributions of interreaction between outgoing electrons and nucleus to the change tendency of differential cross sections in the scattering plane and perpendicular plane are stronger.
引文
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[4]Wang Q,Jia C C,Zhang L M,et al.Triply differential cross-sections for(e,2e)process of Ne in the coplanar double-symmetric geometry[J].J.At.Mol.Phys.,2015,32:998(in Chinese)[王琦,贾昌春,张立民,等.共面双对称几何条件下Ne原子(e,2e)反应的三重微分截面[J].原子与分子物理学报,2015,32:998]
[5]Abdel-Naby S A,Pindzola M S,Pearce A J,et al.Electron-impact ionization of the N atom[J].J.Phys.B:At.Mol.Opt.Phys.,2015,48:025203.
[6]Bray I,Guilfoile C J,Kadyrov A S,et al.Ionization amplitudes in electron-hydrogen collisions[J].Phys.Rev.A.,2014,90:022710.
[7]Harris A L,Esposito T P.Projectile interaction effects in out-of-plane excitation-ionization of helium[J].J.Phys.B:At.Mol.Opt.Phys.,2015,48:215201.
[8]Dürr M,Dimopoulou C,Najjari B,et al.Higher-order contributions observed in three-dimensional(e,2e)cross-section measurements at 1-ke V impact energy[J].Phys.Rev.A.,2008,77:032717.
[9]Yang H,Xing L L,Zhang S M,et al.Influence of screening effect on double differential cross section and single differential cross section for(e,2e)process of helium[J].Acta Phys.Sin.,2013,62:183402(in Chinese)[杨欢,邢玲玲,张穂萌,等.屏蔽效应对氦原子(e,2e)反应中二重微分截面和单微分截面的影响[J].物理学报,2013,62:183402]
[10]Yang H,Zhang S M,Xing L L,et al.A theoretical study on double differential cross sections for(e,2e)process of hydrogen[J].Acta Phys.Sin.,2012,61:133401(in Chinese)[杨欢,张穂萌,邢玲玲,等.氢原子(e,2e)反应中二重微分截面的理论研究[J].物理学报,2012,61:133401]
[11]Zhang S M.Momentum correlation in the three-body coulomb continuum problem[J].J.Phys.B:At.Mol.Opt.Phys.,2000,33:3545.
[12]Byron F W,Jr,Joachain C J.Correlation effects in atoms.I.helium[J].Phys.Rev.,1966 146:1.
[13]Brauner M,Briggs J S,Klar H.Triply-differential cross sections for ionisation of hydrogen atoms by electrons and positrons[J].J.Phys.B:At.Mol.Opt.Phys.,1989,22:2265.
[14]Berakdar J,Briggs J S.Three-body coulomb continuum problem[J].Phys.Rev.Lett.,1994,72:3799.
[15]Berakdar J,Briggs J S.Interference effects in(e,2e)-differential cross sections in doubly symmetric geometry[J].J.Phys.B:At.Mol.Opt.Phys.,1994,27:4271.
[16]Zhang S M,Chen Z J,Xu K Z.Dynamic screening of the(e,2e)processes for low-energy electron impact ionization of helium[J].Acta Phys.Sin.,1999,48:453(in Chinese)[张穗萌,陈长进,徐克尊.低能电子离化He原子(e,2e)反应中的动力学屏蔽[J].物理学报,1999,48:453]