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.
Categories: physics.chem-ph