Knowledge Bank

The study of acid-water clusters is an active area of research due to its fundamental importance for chemistry$,$, Int. Rev. Phys. Chem. 21, 277 (2002).}. In particular the (HCl)(H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$O) clusters have been extensively investigated both theoretically and experimentally as a benchmark system. Despite of the great effort devoted to its understanding HCl dissociation in water clusters is still not well understood. An IR-Spectroscopy study on (HCl)(H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow>}$O) embedded in helium nanodroplets will be presented. The H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow><mrow\; data-mjx-texclass="ORD">16</mrow>}$O$\to$H$\mathrm{<mrow\; data-mjx-texclass="ORD">2</mrow><mrow\; data-mjx-texclass="ORD">18</mrow>}$O and isotopic substitution was used in the experiments to probe the bands in the 2650-2760 cm$\mathrm{<mrow\; data-mjx-texclass="ORD">-1</mrow>}$ spectral range which has been object of some debate recently, Science 324, 1545 (2009).}$,$, Phys. Chem. Lett. 1, 2233 (2010).}. The observed isotopic shifts for the different bands raise some new questions to be addressed.