Photodissociation cross sections of ${\mathrm{Ne}}_2^{+}$, ${\mathrm{Ar}}_2^{+}$, ${\mathrm{Kr}}_2^{+}$, and ${\mathrm{Xe}}_2^{+}$ from 3500 to 5400 Å

The photodissociation (photoabsorption) cross sections of ${\mathrm{Ne}}_2^{+}$, ${\mathrm{Ar}}_2^{+}$, ${\mathrm{Kr}}_2^{+}$, and ${\mathrm{Xe}}_2^{+}$ have been measured from 3500 to 5400 Å. The rare-gas dimer ions were produced in a drift-tube mass spectrometer, and the ${\mathrm{Kr}}^{+}$ and ${\mathrm{Ar}}^{+}$ ion laser lines were used as the photon source. The cross sections decrease monotonically with increasing photon wavelength from 3500 to 5000 Å, and then increase with photon wavelength. The cross sections have values of 1.93, 13.3, 24.8, and 29.6 × ${10}^{-18\mathrm{}}$ ${\mathrm{cm}}^2$ at (3569 and 3507) Å for ${\mathrm{Ne}}_2^{+}$, ${\mathrm{Ar}}_2^{+}$, ${\mathrm{Kr}}_2^{+}$, and ${\mathrm{Xe}}_2^{+}$, respectively. The current measurements are compared with various theoretical calculations. The dependence of the ${\mathrm{Ne}}_2^{+}$ and ${\mathrm{Ar}}_2^{+}$ cross sections on the effective kinetic temperature was investigated by increasing the ion drift velocity, and was attributed to vibrational excitation of the ions.