一种考虑几何屏蔽效应的计算“电子-分子”散射总截面的可加性规则修正方法  

A modification method of additivity rule for total cross section calculations of electron scattering from molecules considering the geometric shielding effect

作　　者：施德恒[1] 孙金锋[2] 朱遵略[2] 刘玉芳[2] 

机构地区：[1]信阳师范学院物理电子工程学院,信阳464000 [2]河南师范大学物理与信息工程学院,新乡453007

出　　处：《物理学报》2008年第3期1632-1639,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10574039);河南省高校科技创新人才支持计划(批准号:2008KJCX009);河南省教育厅自然科学研究计划项目(批准号:2007140015)资助的课题~~

摘　　要：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—5000eV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算,所得结果要比利用未修正的可加性规则及其他理论进行计算所得结果更接近实验值.同时分析也表明,为使未修正的可加性规则能够在一个较大的能区内直接用于"电子-分子"散射总截面的计算,必须改造适用于"电子-自由原子"散射总截面计算的复光学势,以解决它用于"电子-分子中的原子"散射总截面的计算时,在中低能区过强、且随电子入射能量的增加而衰减太快的问题.Taking into consideration the changes of the geometric shielding effect in a molecule as the incident electron energy varies, a modification method of additivity rule model for total cross section calculations of electron scattering from molecules at intermediate and high energies, is presented. Employing the modified additivity rule model, the total cross sections for electron scattering from NO, N2 O, NO2 and C2 H6 are calculated over a wide energy range from 50 to 5000 eV by using the experimental results of electron scattering from atoms C, N, H and O. The calculated values of total cross sections are compared with those obtained by measurements and other theories wherever available, and good agreement is attained over a wide energy range. It is shown that the total cross sections obtained by the modified additivity rule model are much closer to the measurements than the unmodified one and other theories. And it is also shown that the modification of complex optical potential must be related with energy of incident electrons so that the potential for total cross section calculations of electron scattering from free atoms is made suitable for the total cross section calculations of electron scattering from the ones in the molecule.

关 键 词：电子散射 可加性规则 总截面 几何屏蔽效应 修正方法 

分 类 号：O561[理学—原子与分子物理]