${\mathit{O}}_{\mathit{u}}^{+}$${(}^3$${\mathrm{\Pi }}_{\mathit{u}}$)←${\mathit{XO}}_{\mathit{g}}^{+}$(${\mathrm{\Sigma }}_{\mathit{g}}^{+}$) transitions in ${\mathrm{Cd}}_2$ excited in crossed molecular and laser beams

Excitation spectra of ${\mathrm{Cd}}_2$ van der Waals molecules produced in a molecular beam employing free-jet supersonic expansion, crossed with a pulsed dye-laser beam, were studied using He, Ne, and Ar as carrier gases. Well-resolved structures, arising from transitions between the vibrational levels of the ${\mathrm{XO}}_g^{+}$ ${(}^1$ ${\Sigma }_g^{+}$) and $O_u^{+}$ ${(}^3$ ${\Pi }_u$) states, were recorded at various translational temperatures. An analysis of the spectra yielded the vibrational constants and bond strengths of the molecule in the two electronic states. The lifetimes of the Cd(5 ${}_{}{}^3{}_{}{}^{}P_1^{}{}_{}{}^{}$) atoms and ${\mathrm{Cd}}_2$(${\mathrm{O}}_{\mathrm{u}}^{+}$) molecules in various vibrational states were also determined.