Elastic differential cross sections of electron scattering by CF_4 at intermediate energies

1　ＩＮＴＲＯＤＵＣＴＩＯＮＣａｒｂｏｎｔｅｔｒａｆｌｕｏｒｉｄｅ(ＣＦ4)ｉｓｏｎｅｏｆｔｈｅｍｏｓｔｗｉｄｅｌｙｕｓｅｄｃｏｍｐｏｎｅｎｔｓｏｆｆｅｅｄｇａｓｍｉｘｔｕｒｅｓｅｍｐｌｏｙｅｄｆｏｒａｖａｒｉｅｔｙｏｆｐｌａｓｍａａｓｓｉｓｔｅｄｍａｔ...     

Elastic differential cross sections of electron scattering by CF_4 at intermediate energies

The elastic differential cross sections(DCS)for electron scattering from CF 4 are calculated at six impact energies(in 100—700 eV)employing the independent atom model(IAM)with partial waves. The atoms are presented by a model complex optical potential which is composed of static, exchange, polarization, and absorption terms. The electron density function ρ(r) is obtained by a fitting procedue to the Dirac Hartree Fock Slater sef consistent data. Compared with available experimental data, the presen...     

低能电子入射电离He原子二重微分截面的理论研究

研究了低能电子入射单电离He原子的二重微分截面(DDCS)，通过对散射电子三重微分截面在全空间的角度积分得到敲出电子的DDCS.分别用DS3C模型和BBK模型计算了入射能为26.3，28.3，30.3，32.5，34.3，36.5和40.7eV时，低能电子入射电离He原子的DDCS；研究表明：DS3C的计算结果，除在低入射能(比如26.3eV)和小敲出角之外，均能与绝对测量的实验结果较好地符合.此外，对直接和交换效应也进行了研究，给出了交换效应对截面的贡献.     

中高能电子被甲烷及氯代甲烷散射的总截面

利用可加性规则，使用HartreeFock波函数，采用由束缚原子概念修正过的复光学势（由静 电势、交换势、修正极化势及吸收势这四部分组成），在较大的能量(30—5000eV)范围内对 电子被甲烷及氯代甲烷（CH₄，CCl₄，CHCl₃，CH₂Cl₂和CH ₃Cl）散射的总截面进行了计算，且将计算结果与实验结果及其他理论计算 结果进行 了比较.结果表明，利用被束缚原子概念修正过的复光学势及可加性规则进行计算，所得结 果的精度要比利用未被束缚原子概念修正的复光学势及可加性规则进行计算得到的结果好很 多.因此，在复光学势中采用束缚原子概念可提高电子被分子散射的总截面的计算准确度. 关键词： 电子散射 可加性规则 束缚原子 总截面     

中低速C3+与He，Ne，Ar原子相互作用过程中单电子转移绝对截面的测量

实验测量了1.7v₀—4.2v₀(v₀为玻尔速度,v₀=2.19×10⁸cm/s)的C³⁺与He,Ne,Ar原子碰撞过程中单电子转移绝对截面.将实验结果与多体经典轨道蒙特卡罗模拟计算结果做了比较,发现测量结果与多体经典轨道蒙特卡罗模拟计算结果在趋势上相符.当入射离子速度在1.7v₀—2 关键词： 离子-原子碰撞 单电子转移 绝对截面     

Electrical conductance at initial stage in epitaxial growth of Pb, Ag, Au and In on modified Si(1 1 1) surface

The electronic properties of thin metallic films of Pb, Ag, Au and In atoms deposited at 105 K on well defined metallic surface, i.e. Si(1 1 1)-(6 × 6)Au surface with 10 ML of annealed Pb, were investigated using four-point probe method in UHV condition. The structure of the substrate and deposited metals were monitored by the RHEED system. The electrical conductance, measured during the deposition of In and Pb atoms, shows the local minimum for the coverage equals about 0.3 ML whereas for Au and Ag atoms the conductance decreases during the first monolayer growth. For Au atoms the local maximum in the conductance was observed for the coverage about 0.55 ML, which can be connected with localized states. To describe theoretically the conductance behavior the tight-binding Hamiltonian and equation of motion for the Green’s function were used and good qualitative agreement was obtained.