title: NH4(+) Resides Inside the Water 20-mer Cage As Opposed to H3O(+), Which Resides on the Surface: A First Principles Molecular Dynamics Simulation Study.
abstract: Experimental vibrational predissociation spectra of the magic NH4(+)(H2O)20 clusters are close to those of the magic H3O(+)(H2O)20 clusters. It has been assumed that the geometric features of NH4(+)(H2O)20 clusters might be close to those of H3O(+)(H2O)20 clusters, in which H3O(+) resides on the surface. Car-Parrinello molecular dynamics simulations in conjunction with density functional theory calculations are performed to generate the infrared spectra of the magic NH4(+)(H2O)20 clusters. In comparison with the experimental vibrational predissociation spectra of NH4(+)(H2O)20, we find that NH4(+) is inside the cage structure of NH4(+)(H2O)20 as opposed to on the surface structure. This shows a clear distinction between the structures of NH4(+)(H2O)20 and H3O(+)(H2O)20 as well as between the hydration phenomena of NH4(+) and H3O(+).
authors.affiliation: Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology , San 31, Hyojadong, Namgu, Pohang 790-784, Korea.
authors.forename: Soohaeng Yoo
authors.initials: SY
authors.lastname: Willow
authors.affiliation: Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology , San 31, Hyojadong, Namgu, Pohang 790-784, Korea.
authors.forename: N Jiten
authors.initials: NJ
authors.lastname: Singh
authors.affiliation: Center for Superfunctional Materials, Department of Chemistry, Pohang University of Science and Technology , San 31, Hyojadong, Namgu, Pohang 790-784, Korea.
authors.forename: Kwang S
authors.initials: KS
authors.lastname: Kim