Elastic electron scattering from ortho-, meta-, and paraxylenes, C8H10

Abstract

Ab intio calculations and normalized experimental measurements of the differential and integral cross sections for vibrationally elastic scattering of low-energy electrons from orthoxylene, meta-xylene and para-xylene are presented. The calculated cross sections are obtained using the Schwinger multichannel method implemented with norm-conserving pseudopotentials. The differential cross sections are measured at incident energies from 1 eV to 30 eV and scattering angles from 10 o to 130 o. These cross sections are compared to experimental results for toluene. The comparisons illuminate the role of molecular structure in determining the integral cross sections and the angular distributions of resonantly scattered electrons.

Elastic electron scattering from chlorobenzene

“…Later work by our group for toluene by Sakaamini et al [18] showed good agreement with those of Kato et al [17] except at the lowest E 0 of 1.5 eV where we see a stronger dipole forward-scattering in significantly better agreement with the SMC theory [18]. Our group has also measured low energy elastic scattering for the ortho-, meta, and para-isomers of xylene (C 6 H 4 (CH 3 ) 2 ) [19] and find the DCSs of these isomers to be essentially very similar, but about a factor of two higher in magnitude than toluene, importantly showing the significance of the extra-CH 3 groups which were attached to the benzene ring to form toluene into xylene [19]. Our group has also measured elastic scattering from benzonitrile (C 6 H 5 CN), which has a nitrile (C ≡ N) radical attached to the benzene ring [20], at similar low E 0 values.…”

“…Figure 5. Experimental DCSs for elastic scattering from several benzene related compounds (a) all at E 0 = 15 eV, (b) all at E 0 = 30 eV, except toluene at E 0 = 20 eV.Cho et al[16]; Sakaamini et al[18]; Khakoo et al[20]; (•) Sakaamini et al[19]; present work; Kato et al[17]; ( ) Cho et al[16].…”

“…The experimental ICSs and MTCSs were obtained by extrapolating the DCSs to θ ≈ 0 • and to 180 • and then integrating the DCSs as e.g. described in previous work [18,19,44]. Since chlorobenzene is a polar molecule, the long-range interaction due to the molecular dipole moment gives rise to a steep variation of the DCS in the region of small scattering angles which are not covered by the experiments making the extrapolation procedure essentially arbitrary [45].…”

“…The V ab was described in the framework of the scaled quasi-free scattering model (SQFSM) potential of Lee et al [49]. A single-center-expansion about the center of mass of the molecule was applied in terms of symmetry-adapted functions to the molecular wave function and interaction potentials [50], and the scattering equations were solved iteratively by the Cho et al [16]; Sakaamini et al [18]; Khakoo et al [20]; (•) Sakaamini et al [19]; present work; Kato et al [17]; ( ) Cho et al [16].…”

Elastic scattering of low-energy electrons from toluene

“…In the present work, we present integral, differential and momentum transfer cross sections for elastic scattering from toluene as part of an effort to study benzene derivatives with substituting a -CH 3 group on one of the -H groups. We have also planned similar work on substituting two -CH 3 groups to produce o-xylene, m-xylene and p-xylene [13]. For all these targets we have conducted a joint experimental and theoretical study to provide low energy differential elastic and integral cross sections, and to compare our results with theory and other available (experimental) cross sections.…”