Elastic scattering of electrons from dimethylsulfide and dimethylsulfoxide

Abstract

Differential cross sections for elastic scattering of electrons from dimethylsulfide and dimethylsulfoxide in the energy range from 30 to 500 eV are presented. The cross sections have been measured using a crossedbeam-type high-resolution electron spectrometer. The measured cross sections have been put on an absolute scale using the relative flow technique. The measured differential cross sections show an increase in the midangles at 30 and 50 eV for both the molecules that is characteristic of resonant enhanced d-wave scattering. Total and momentum-transfer cross sections were derived by integrating over all angles after extrapolating the data to forward and backward angles using a least-squares fitting procedure based on the Legendre polynomial expansion. Independent-atom-model-based theoretical calculations incorporating static, exchange, and polarization potentials are also reported and compared with the experimental cross sections. For energies lower than 100 eV, it is seen that the independent-atom-model calculations fail to predict the qualitative behavior of the differential cross sections correctly, while at energies greater than 100 eV it seems to describe the data adequately. The effect of polarization and enhancement of cross sections through d-wave scattering at low energies is also analyzed.

Electron scattering studies of DMS, DMDS and DMSO homologous series

“…DMS is the first and the most important molecule of the DMS family. The present Q el data is in excellent agreement with the measurements and theoretical calculations of Rao et al [9]. However, both experimental and theoretical values of Homem et al [10] have higher values than the present Q el curve at energies beyond 50 eV.…”

“…Similarly, Figure 7 shows the Q el plot for all the three members of the DMDS homologous series as no data is available in the literature. Figure 8 shows the Q el curve for DMSO target with the only available comparison of Rao et al [9]. The present cross sections are slightly lower than the theoretical data of Rao et al [9] however, in good agreement with their measured values.…”

“…Figure 8 shows the Q el curve for DMSO target with the only available comparison of Rao et al [9]. The present cross sections are slightly lower than the theoretical data of Rao et al [9] however, in good agreement with their measured values. In Figure 9, the elastic cross sections of the last two members of DMSO family are plotted together since there is no available study for these molecules to the best of our knowledge.…”

“…Hence, for large non-spherical molecules, with high polarisability, pseudo-structures may arise due to this reason. A broad shoulder is also observed in the measurements and theoretical values of Rao et al [9] for DMSO molecule as shown in Figure 8. However, they have not assigned any reason for this structure.…”

“…For elastic cross section (Q el ), the comparisons are available for DMS and DMSO molecules only. Rao et al [9] reported both experimental and theoretical data for DMS and DMSO molecules. Homem et al [10] also investigated electron scattering from DMS molecules experimentally and theoretically.…”