Interactions of ${\mathrm{Ne}}_2$ Rydberg states with dissociation and ${\mathrm{Ne}}_2^{+}$ (${\mathit{X}}^2$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$, ${\mathit{v}}^{+}$=0–2) ionization continua

Laser excitation (photodissociation) and absorption spectroscopy of ${\mathrm{Ne}}_2$ ${\mathit{a}}^3$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ beyond the ${\mathit{v}}^{+}$=0 limit of the ${\mathrm{Ne}}_2^{+}$ ground electronic state (${\mathit{X}}^2$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$) has revealed several distinct series of Fano-type windows superimposed onto predissociative and absorption continua. Resonances attributed to npσ←${\mathit{a}}^3$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ Rydberg-Rydberg transitions converging to ${\mathit{v}}^{+}$=1–3 of the ${\mathit{X}}^2$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ state are observed but apparent windows appear in the ${\mathit{a}}^3$${\mathrm{\Sigma }}_{\mathit{u}}^{+}$ absorption spectrum only for ${\mathit{v}}^{+}$=1 ion core Rydberg states. In contrast, IallR ${\mathit{v}}^{+}$=2 and 3 ion core states occur as positive absorptions. Comparison of the photoabsorption and excitation spectra shows clear evidences of the competition between autoionization and predissociation, but the general dominance of dissociation as the exit channel.