Additivity Rule for Electron–Molecule Total Cross Section Calculations at 50–5000 eV: A Geometrical Approach

To quantify the changes of the geometric shielding effect in a molecule as the incident electron energy varies, we present an empirical fraction, which represents the total cross section (TCS) contributions of shielded atoms in a molecule at different energies. Using this empirical fraction, a new formulation of the additivity rule is proposed. Using this new additivity rule, the TCSs for electron scattering by CO2, C2H2, C6H12 (cyclo-hexane) and C8H16 (cyclo-octane) are calculated in the range 50–5000 eV. Here the atomic cross sections are derived from the experimental TCS results of simple molecules (H2, O2, CO). The quantitative TCSs are compared with those obtained by experiments and other theories, and good agreement is attained over a wide energy range.

[1]  C. Makochekanwa,et al.  Positron and electron scattering from alkane molecules , 2006 .

[2]  K. N. Joshipura,et al.  Electron impact total and ionization cross-sections for some hydrocarbon molecules and radicals , 2006 .

[3]  C. Makochekanwa,et al.  Total cross-section measurements for positrons and electrons colliding with alkane molecules : Normal hexane and cyclohexane , 2005 .

[4]  Yang Xiang-dong,et al.  A Correlation Potential Method for Electron Scattering Total Cross Section Calculations on Several Diatomic and Polyatomic Molecules over Energy Range 10∼5000 eV , 2005 .

[5]  K. N. Joshipura,et al.  Total and ionization cross sections of electron scattering by fluorocarbons , 2005 .

[6]  Zun-lue Zhu,et al.  Total Cross Sections for Electron Scattering from the Isoelectronic (Z = 14) Molecules (C2H2, CO, HCN and N2) at 100–5000 eV , 2004 .

[7]  G. García,et al.  Screening corrections for calculation of electron scattering from polyatomic molecules , 2003 .

[8]  D. Powers,et al.  Total electron scattering cross sections of CH{sub 4}, C{sub 2}H{sub 2}, C{sub 2}H{sub 4}, and C{sub 2}H{sub 6} in the energy range 200-1400 eV , 2002 .

[9]  Jinfeng Sun,et al.  Additivity rule for the calculation of electron scattering from polyatomic molecules , 2000 .

[10]  A. Zecca,et al.  Additivity rule for electron-molecule cross section calculation: A geometrical approach , 1999 .

[11]  K. N. Joshipura,et al.  Various total cross-sections for electron impact on C2H2, C2H4 and CH3X (X = CH3, OH, F, NH2) , 1999 .

[12]  Jinfeng Sun,et al.  Geometric shielding effects of electron scattering from polyatomic molecules , 1997 .

[13]  G. García,et al.  Correlation of the total cross section for electron scattering by molecules with 10–22 electrons, and some molecular parameters at intermediate energies , 1997 .

[14]  Jinfeng Sun,et al.  Simple model for the calculation of total cross sections for electron scattering from polyatomic molecules , 1997 .

[15]  T. Märk,et al.  A MODIFIED ADDITIVITY RULE FOR THE CALCULATION OF ELECTRON IMPACT IONIZATION CROSS-SECTION OF MOLECULES ABN , 1997 .

[16]  K. N. Joshipura,et al.  Total electron scattering cross sections for NO, CO, , , and eV) , 1996 .

[17]  A. Osborne,et al.  Wind and waves in the Northern Adriatic Sea , 1996 .

[18]  García,et al.  Total cross sections for electron scattering by CO2 molecules in the energy range 400-5000 eV. , 1996, Physical review. A, Atomic, molecular, and optical physics.

[19]  Chen,et al.  Absolute total-cross-section measurements for intermediate-energy electron scattering on C2H2 and CO. , 1995, Physical review. A, Atomic, molecular, and optical physics.

[20]  K. N. Joshipura,et al.  Electron impact total (elastic + inelastic) cross-sections of C, N & O atoms and their simple molecules , 1994 .

[21]  W. J. Zande,et al.  Simple models for the calculation of photoionization and electron impact ionization cross sections of polyatomic molecules , 1994 .

[22]  A. Zecca,et al.  Total cross-section measurements for e−—CO scattering: 80–4000 eV , 1993 .

[23]  Jain,et al.  Total (elastic plus inelastic) cross sections for electron scattering from diatomic and polyatomic molecules at 10-5000 eV: H2, Li2, HF, CH4, N2, CO, C2H2, HCN, O2, HCl, H2S, PH3, SiH4, and CO2. , 1992, Physical review. A, Atomic, molecular, and optical physics.

[24]  D. Raj.  A note on the use of the additivity rule for electron-molecule elastic scattering , 1991 .

[25]  O. Sueoka,et al.  Total cross section measurements for 1-400 eV positrons and electrons in C2H2 , 1989 .

[26]  A. Zecca,et al.  Absolute total cross sections for electron-CO2 scattering at energies form 0.5 to 3000 eV , 1987 .

[27]  W. Kauppila,et al.  e(-CO and e(-CO/sub 2/ total cross-section measurements , 1983 .