Two-body fragmentation of ${\mathrm{N}}_2{\mathrm{O}}^{q+}$ ($q=2,3$) induced by electron-capture collision of $5.7-\mathrm{keV}/\mathrm{u}\mathrm{X}{\mathrm{e}}^{15+}$ is studied. Through the triply coincident measurement on ion-pair fragments with the scattered projectile and the correlation analysis on the ion-pair time of flight and momentum conservation, we have clearly identified 12 reaction channels for the formation and dissociation of ${\mathrm{N}}_2{\mathrm{O}}^{2+}$ and ${\mathrm{N}}_2{\mathrm{O}}^{3+}$. The fraction ratios for these channels and the corresponding kinetic energy release (KER) distributions for the ion-pair products have been obtained. Calculations of the potential energy curves of ${\mathrm{N}}_2{\mathrm{O}}^{3+}$ for the N-N and N-O bond stretches are performed using the complete active space self-consistent field method. The KER spectra for the two-body fragmentation of ${\mathrm{N}}_2{\mathrm{O}}^{2+}\to {\mathrm{N}}^{+}+\mathrm{N}{\mathrm{O}}^{+}$ and $\mathrm{N}{{}_2}^{+}+{\mathrm{O}}^{+}$ can be explained by the decay via the $X{}^3\mathrm{\Sigma }^{-}$ and $1{}^3\mathrm{\Pi }$ states, and the major peaks or structures observed in the KER spectra for ${\mathrm{N}}_2{\mathrm{O}}^{3+}\to {\mathrm{N}}^{+}+\mathrm{N}{\mathrm{O}}^{2+}$ can be attributed to the $1{}^2\mathrm{\Pi }, 2{}^2\mathrm{\Pi }$, and $2{}^2\mathrm{\Sigma }^{-}$ states, whereas those in the KER spectra for ${\mathrm{N}}_2{\mathrm{O}}^{3+}\to {\mathrm{O}}^{+}+{\mathrm{N}}_2^{2+}$ are mainly contributed from the $1{}^2\mathrm{\Pi }, 3{}^2\mathrm{\Pi }$, and $4{}^2\mathrm{\Pi }$ states. In addition, we found that the KER structures for the same ion-pair products are not sensitive to the number of electrons stabilized at the projectile, but the KER intensities are clearly dependent on it. The mechanism of multielectron captures of the projectile to form the transient multicharged molecular ions and the following projectile stabilization with or without autoionizing cascades is proposed to explain it.

• Received 5 December 2018

DOI:https://doi.org/10.1103/PhysRevA.99.012710