Knowledge Bank

The weakly bound complexes $Al-(H2O)$ and $Al-(D2O)$ are prepared with pulsed laser vaporization and studied with single-photon ZEKE-PFI spectroscopy. The spectra consist of progressions in the Al-water stretch in the ground state of the corresponding cations $(Al-(H2O):\omega e+=327.5cm-1)$. The origin energy, Al atom ionization potential and the known $Al+-(H2O)$ bond energy produce a neutral $Al-(H2O)$ bond energy of $D0=1440cm-1$. Partially resolved rotational structure suggests that the cation complexes have $C2v$ structures, while the neutrals are non-planar. The neutral structure and energetics are consistent with a metal-water coordinate-covalent bond, which has been predicted by theory.