The protonated water dimer is a prototypical system for the study of proton transfer in aqueous solution. We report infrared photodissociation spectra of cooled H+(H2O)2 [and D+(D2O2] ions, measured between 620 and 1900 wave numbers (cm-1). The experiment directly probes the shared proton region of the potential energy surface and reveals three strong bands below 1600 cm-1 and one at 1740 cm-1 (for H5O2+). From a comparison to multidimensional quantum calculations, the three lower energy bands were assigned to stretching and bending fundamentals involving the O...H+...O moiety, and the highest energy band was assigned to a terminal water bend. These results highlight the importance of intermode coupling in shared proton systems.
Articles you may be interested inPhotoelectron spectroscopy and ab initio calculations of small SinSm − (n = 1,2; m = 1-4) clusters Electronic structure of vanadium cluster anions as studied by photoelectron spectroscopy Ar n Cl Ϫ clusters have been investigated by anion zero electron kinetic energy ͑ZEKE͒ and partially discriminated threshold photodetachment spectroscopy. The experiments yield size-dependent electron affinities ͑EAs͒ and electronic state splittings for the X, I, and II states accessed by photodetachment. Cluster minimum energy structures have been determined from calculations based on a ''simulated annealing'' approach employing our recently presented Ar-Cl ͑Ϫ͒ pair potentials from anion ZEKE spectroscopy ͓T. Lenzer, I. Yourshaw, M. R. Furlanetto, G. Reiser, and D. M. Neumark, J. Chem. Phys. 110, 9578 ͑1999͔͒ and various nonadditive terms. The EAs calculated without many-body effects overestimate the experimental EAs by up to 1500 cm Ϫ1 . Repulsive many-body induction in the anion clusters is found to be the dominant nonadditive effect. In addition, the attractive interaction between the chloride charge and the Ar 2 exchange quadrupole is important. These findings are consistent with our earlier results for Xe n I Ϫ , Ar n I Ϫ , and Ar n Br Ϫ clusters and highlight again the necessity of an adequate implementation of many-body effects to describe the energetics of such systems. For Ar n Cl Ϫ clusters with nϾ12 we find some deviations between experimental and calculated ͑0 K͒ EA which can be explained by the population of less stable anion structures due to the finite temperatures of the clusters in our experiments. This results in lower EAs than predicted for the corresponding global minimum energy structures.
Origins and modeling of many-body exchange effects in van der Waals clustersXe n I Ϫ van der Waals clusters have been investigated by anion zero electron kinetic energy ͑ZEKE͒ and partially discriminated threshold photodetachment ͑PDTP͒ spectroscopy. The experiments yield size-dependent electron affinities ͑EAs͒ and electronic state splittings between the X, I, and II states accessed by photodetachment. Cluster minimum energy structures have been determined by extensive simulated annealing molecular dynamics calculations using Xe-I ͑Ϫ͒ pair potentials from anion ZEKE spectroscopy and various nonadditive terms. The EAs calculated without many-body effects overestimate the experimental EAs by up to 3000 cm Ϫ1 . Repulsive many-body induction in the anion clusters is found to be the dominant nonadditive effect, though the attractive interaction between the iodide charge and the Xe 2 exchange quadrupole is also important. Unique global minimum energy structures for the anion clusters arise from the influence of the many-body terms, yielding, e.g., arrangements with a closed shell of xenon atoms around the iodide anion for the clusters with nϭ12-14. The specific dependence of the EA curve on cluster size allows us to refine the absolute Xe-I bond lengths for the anion, X, I, and II state diatomic potentials to within Ϯ0.05 Å.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.