Triple-ionization-induced dissociation of NO in strong laser fields

In this paper, we study the dynamics of triple-ionization-induced dissociation in a heteronuclear diatomic molecule $\mathrm{NO}$. Compared to homonuclear diatomic molecules, $\mathrm{NO}$ shows a greater complexity in its final states following triple ionization. By utilizing a well-established technique from the study of sequential versus nonsequential ionization, our study shows that both the ${\mathrm{N}}^{2+}+{\mathrm{O}}^{+}$ and ${\mathrm{N}}^{+}+{\mathrm{O}}^{2+}$ channels are predominately formed nonvertically through a relatively slowly dissociating ${\mathrm{N}}^{+}+{\mathrm{O}}^{+}$ state. Finally, we show that both the ${\mathrm{N}}^{2+}+{\mathrm{O}}^{+}$ and ${\mathrm{N}}^{+}+{\mathrm{O}}^{2+}$ channels are formed at nearly the same internuclear separation that is much smaller than the critical internuclear distance, indicating that dissociative ionization of high charge states in a molecule can occur as a molecule steadily expands from its equilibrium separation rather than always at the critical internuclear distance.