Title: High-resolution photoelectron-spectroscopic investigation of the H$_2$O$^+$ cation in its ${\mathrm {\tilde A^+}}$ electronic state,
Abstract: The photoelectron spectrum of water has been recorded in the vicinity of the
${\mathrm {\tilde A^+}}$ $\leftarrow$ $\tilde{\mathrm{X}}$ transition between
112 000 and 116 000 cm$^{-1}$ (13.89-14.38 eV). The high-resolution allowed the
observation of the rotational structure of several bands. Rotational
assignments of the transitions involving the $\Pi(080)$, $\Sigma(070)$ and
$\Pi(060)$ vibronic states of the $\tilde{\mathrm{A}}^+$ electronic state are
deduced from previous studies of the $\tilde{\mathrm{A}}^+ -
\tilde{\mathrm{X}}^+$ band system of H$_2$O$^+$ (Lew, Can. J. Phys. 54, 2028
(1976) and Huet et al., J. Chem. Phys. 107, 5645 (1997)) and photoionization
selection rules. The transition to the $\Sigma(030)$ vibronic state is
tentatively assigned.