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Differential Elastic Electron Scattering Cross-sections of Trimethyl Phosphate

04.01.2010

For a considerable number of biomolecules, the experimental determination of the electron scattering cross-sections under single-collision conditions is difficult to perform, since these molecules can be transferred into the gas phase only under massive effort or since they affect the measurement due to their aggressive chemical properties. Therefore, it makes sense to develop a theoretical method that enables the computation of the electron scattering cross-sections of such molecules.

In a first stage, the differential elastic scattering cross-sections of tetrahydrofuran were computed by using the modified independent-atom model and compared with experimental results. Figure 1 shows the experimental and the theoretical differential elastic scattering cross-sections of tetrahydrofuran for electrons having a kinetic energy of 80 eV or 1 keV as a function of the scattering angle. It is to be seen that the two data sets are in good agreement over the whole scattering angle range. After the successful testing of the theoretical model on tetrahydrofuran, the differential elastic scattering cross-sections of trimethyl phosphate were computed for different electron energies. As an example, Fig. 2 shows the computed differential elastic scattering cross-sections of trimethyl phosphate for four electron energies compared to those for tetrahydrofuran.

Figure 1 : Differential elastic electron scattering cross-sections of tetrahydrofuran as a function of the scattering angle: () experimental results, (-) computed values.

Figure 2 : Theoretical differential elastic electron scattering cross-sections: (-) tetrahydrofuran, (-) trimethyl phosphate