Hydration of the Calcium Dication: Direct Evidence for Second Shell Formation from Infrared Spectroscopy
- 10 October 2007
- journal article
- research article
- Published by Wiley in Chemphyschem
- Vol. 8 (15), 2245-2253
- https://doi.org/10.1002/cphc.200700404
Abstract
Infrared laser action spectroscopy in a Fourier-transform ion cyclotron resonance mass spectrometer is used in conjunction with ab initio calculations to investigate doubly charged, hydrated clusters of calcium formed by electrospray ionization. Six water molecules coordinate directly to the calcium dication, whereas the seventh water molecule is incorporated into a second solvation shell. Spectral features indicate the presence of multiple structures of Ca(H2O)72+ in which outer-shell water molecules accept either one (single acceptor) or two (double acceptor) hydrogen bonds from inner-shell water molecules. Double-acceptor water molecules are predominately observed in the second solvent shells of clusters containing eight or nine water molecules. Increased hydration results in spectroscopic signatures consistent with additional second-shell water molecules, particularly the appearance of inner-shell water molecules that donate two hydrogen bonds (double donor) to the second solvent shell. This is the first reported use of infrared spectroscopy to investigate shell structure of a hydrated multiply charged cation in the gas phase and illustrates the effectiveness of this method to probe the structures of hydrated ions.Keywords
This publication has 75 references indexed in Scilit:
- Infrared spectroscopy of Cu+(H2O)n and Ag+(H2O)n: Coordination and solvation of noble-metal ionsThe Journal of Chemical Physics, 2007
- Structures, energetics, and spectra of aqua-cesium (I) complexes: An ab initio and experimental studyThe Journal of Chemical Physics, 2007
- Recent advances in understanding the structures of medium-sized protonated water clustersInternational Reviews in Physical Chemistry, 2005
- Infrared Spectrum of the Protonated Water Dimer in the Gas PhaseThe Journal of Physical Chemistry A, 2004
- Infrared Signature of Structures Associated with the H + (H 2 O)
n
( n = 6 to 27) ClustersScience, 2004
- Infrared Spectroscopic Evidence for Protonated Water Clusters Forming Nanoscale CagesScience, 2004
- Gas-Phase Infrared Spectrum of the Protonated Water DimerScience, 2003
- Building Solutions--One Molecule at a TimeScience, 2003
- Vibrational predissociation spectroscopy of Cs+(H2O)1−5The Journal of Chemical Physics, 1996
- Vibrational spectroscopy of the hydrated hydronium cluster ions H3O+⋅(H2O)n (n=1, 2, 3)The Journal of Chemical Physics, 1989