Spin-orbit selectivity observed for the ${\mathrm{HCl}}^{+}$$\left(\tilde{X}{}^2\Pi \right)$ state using resonant photoemission

We report the experimental observation of a strongly selective population of the spin-orbit components in the ${\mathrm{HCl}}^{+}$ $\tilde{X}{}^2{\Pi }_{\Omega }$ states after excitation into the dissociative ${2p}^{-1}6{\sigma }^{*}$ core excited state. A progression of highly excited vibrational states with either the $\Omega =3/2\mathrm{}$ or $\Omega =1/2\mathrm{}$ component of the final state is populated, respectively, when the excitation is tuned in the ${2p}_{3/2}^{-1}6{\sigma }^{*}$ or ${2p}_{1/2}^{-1}6{\sigma }^{*}$ part of the resonance. This effect is explained theoretically to be due to the orientational selectivity of the excitation process and the preference of the $L_{2,3}\mathrm{VV}$ Auger process to produce valence holes with the same orientation as the core holes.