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The stopping power of liquid water was measured for carbon ions with energies in the Bragg peak region using the inverted Doppler shift attenuation method. Among the semiempirical data, the results of this work agree best with the data recommended in the Errata and Addendum of ICRU Report No. 73, which is based on an I value of 78 eV for water. The agreement was worse when the present results were compared to the newer recommendation of the ICRU published in ICRU Report No. 90. The srim code seems to slightly overestimate the stopping power of water for carbon ions above 3 MeV. A semiexperimental stopping power of water for α particles was derived from the present results using the theoretical ratio between the stopping powers of water for carbon ions and α particles computed by means of the casp code. These values agree well with the experimental data for α particles within the uncertainties.

As a further test of advanced theoretical methods to describe electron-impact single-ionization processes in complex atomic targets, we extended our recent work on $\mathrm{Ne}(2p$) ionization [X. Ren, S. Amami, O. Zatsarinny, T. Pfl\"uger, M. Weyland, W. Y. Baek, H. Rabus, K. Bartschat, D. Madison, and A. Dorn, Phys. Rev. A 91, 032707 (2015)] to $\mathrm{Ar}(3p$) ionization at the relatively low incident energy of ${E}_{0}=66$ eV. The experimental data were obtained with a reaction microscope, which can cover nearly the entire $4\ensuremath{\pi}$ solid angle for the secondary electron emission. We present experimental data for detection angles of 10, 15, and ${20}^{\ensuremath{\circ}}$ for the faster of the two outgoing electrons as a function of the detection angle of the secondary electron with energies of 3, 5, and 10 eV, respectively. Comparison with theoretical predictions from a $B$-spline $R$-matrix (BSR) with pseudostates approach and a three-body distorted-wave (3DW) approach, for detection of the secondary electron in three orthogonal planes as well as the entire solid angle, shows overall satisfactory agreement between experiment and the BSR results, whereas the 3DW approach faces difficulties in predicting some of the details of the angular distributions. These findings are different from our earlier work on $\mathrm{Ne}(2p$), where both the BSR and 3DW approaches yielded comparable levels of agreement with the experimental data.

Total electron-scattering cross sections of pyrimidine, the basic component for the nucleic bases cytosine and thymine, were measured for electron energies from 5 eV to 1 keV using the linear transmission method. The measured results were compared to semiempirical data obtained by means of the additivity rule and to experimental data for benzene since it has a similar ring structure and the same number of valence electrons as pyrimidine. Furthermore, integral elastic and inelastic electron-scattering cross sections of pyrimidine were calculated by applying the spherical complex optical potential model. The sum of both cross sections agrees reasonably well with the experimental total electron-scattering cross sections of pyrimidine in the energy range from 20 eV to 1 keV. The experimental data are, however, significantly lower than the theoretical cross sections when including the contribution of rotational excitations to the electron scattering.

Differential elastic scattering cross sections of tetrahydrofuran for electrons were measured absolutely in the energy range from 20 eV to 1 keV at scattering angles between 5\ifmmode^\circ\else\textdegree\fi{} and 135\ifmmode^\circ\else\textdegree\fi{}. The measurements were carried out using a crossed-beam arrangement without the application of the widely used relative flow technique. The experimental differential scattering cross sections could be put on an absolute scale by means of the total electron scattering cross sections of tetrahydrofuran and of the current loss of the primary electron beam in the forward direction arising due to the scattering by the molecular beam. The total scattering cross sections were determined for electron energies between 6 eV and 1 keV using a separate linear transmission experiment. The differential cross sections of tetrahydrofuran for the elastic scattering of electrons were also calculated in the energy range between 60 eV and 1 keV by applying the modified independent-atom model. A comparison with the experimental results showed a satisfactory agreement, indicating that the selected theoretical model is adequate for these calculations.

Etude de l'evolution au voisinage de la temperature critique des rendements electroniques totals et de fluorescence, determines par absorption de rayons X dans des configurations de type NEXAFS et EXAFS