Threshold collision-induced dissociation of Sr(2+)(H(2)O)(x) complexes (x=1-6): An experimental and theoretical investigation of the complete inner shell hydration energies of Sr(2+).
The sequential bond energies of Sr(2+)(H(2)O)(x) complexes, where x=1-6, are determined by threshold collision-induced dissociation using a guided ion beam tandem mass spectrometer equipped with an electrospray ionization source. The electrospray source produces an initial distribution of Sr(2+)(H(2)O)(x) complexes, where x=6-9. Smaller Sr(2+)(H(2)O)(x) complexes, where x=1-5, are accessed using a recently developed in-source fragmentation technique that takes place in the high pressure region of a rf-only hexapole ion guide. This work constitutes the first experimental study for the complete inner shell of any multiply charged ion. The kinetic energy dependent cross sections are determined over a wide energy range to monitor all possible dissociation products and are modeled to obtain 0 and 298 K binding energies for loss of a single water molecule. These binding energies decrease monotonically for the Sr(2+)(H(2)O) complex to Sr(2+)(H(2)O)(6). Our experimental results agree well with previous literature results obtained by equilibrium and kinetic studies for x=5 and 6. Because there has been limited theory for the hydration of Sr(2+), we also present an in-depth theoretical study on the energetics of the Sr(2+)(H(2)O)(x) systems by employing several levels of theory with multiple effective core potentials for Sr and different basis sets for the water molecules.
Carl
D R
DR
Department of Chemistry, University of Utah, 315 S. 1400 E. Room 2020, Salt Lake City, Utah 84112, USA.
Chatterjee
B K
BK
Armentrout
P B
PB
D003198:Computer Simulation; D046911:Macromolecular Substances / Q000737:chemistry; D013058:Mass Spectrometry; D008956:Models, Chemical; D008958:Models, Molecular; D013324:Strontium / Q000737:chemistry*; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
D046911:Macromolecular Substances; D014867:Water; D013324:Strontium