# Fitting parameters *a*_{i} of the fifth-order polynomial alpha (T_{e}) = sum ^5_{i=0} a_i T_e^i and scaling parameters *E*_{0} to reproduce the scaled PRC for Sn^{4 +} through Sn^{13 +} ions

_{i}

**Table 3.** Fitting parameters *a _{i}* of the fifth-order polynomial \alpha (T_{e}) = \sum ^5_{i=0} a_i T_e^i and scaling parameters

*E*

_{0}to reproduce the scaled PRC for Sn

^{4 +}through Sn

^{13 +}ions. The numbers in square brackets are powers of 10 to be multiplied with the preceding numbers, respectively.

**Abstract**

Electron-impact single-ionization cross sections of Sn^{q +} ions in charge states *q* = 4–13 with 4d^{[10 − (q − 4)]} outer-shell configurations have been studied in the energy range from the corresponding thresholds up to 1000 eV. Absolute cross sections and fine-step energy-scan data have been measured employing the crossed-beams technique. Contributions of different ionization mechanisms have been analysed by comparing the experimental data with calculations employing the configuration-averaged distorted wave approximation. Ionization plasma rate coefficients inferred from the experimental data are also presented.