Structure and dynamics of HD${}^{+}$ in the vicinity of the H${}^{+}$ + D and D${}^{+}$ + H dissociation thresholds: Feshbach resonances and the role of g/u-symmetry breaking

Abstract

We report on the measurement and analysis of photoionisation, mass-analysed-threshold-ionisation and pulsed-field-ionisation zero-kinetic-energy photoelectron spectra of HD in the vicinity of the dissociative-ionisation thresholds H${}^{+}$ + D(1s) + e${}^{-}$ and H(1s) + D${}^{+}$ + e${}^{-}$. The spectra were recorded via the $v=11$-13 vibrational levels of the $\bar{\mathrm{H}}$ and $\bar{\mathrm{B}}$ outer wells of the H$\bar{\mathrm{H}}$~${}^1{\Sigma }_g^{+}$ and B${}^{\prime \prime }\bar{\mathrm{B}}$~${}^1{\Sigma }_u^{+}$ states and provide information on the weakly bound levels of the X${}^{+}$ ${}^2{\Sigma }_g^{+}$ ground state of HD${}^{+}$ with vibrational quantum numbers $v^{+}=16$-21 and rotational angular-momentum quantum numbers $N^{+}=0$-10. The spectra also reveal for the first time shape and Feshbach resonances of HD${}^{+}$ located energetically above the H${}^{+}$ + D(1s) dissociation limit. The structure and dissociation dynamics of the $\bar{\mathrm{H}}$ and $\bar{\mathrm{B}}$ states of HD and of the X${}^{+}$ ${}^2{\Sigma }_g^{+}$ and A${}^{+}$ ${}^2{\Sigma }_u^{+}$ states of HD${}^{+}$ near the dissociation thresholds are strongly influenced by the g/u-symmetry breaking caused by the nuclear-mass asymmetry.

arXiv comment21 pages, 10 figures

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