title: Comparison Studies on Sub-Nanometer-Sized Ion Clusters in Aqueous Solutions: Vibrational Energy Transfers, MD Simulations, and Neutron Scattering.
abstract: In this work, MD simulations with two different force fields, vibrational energy relaxation and resonant energy transfer experiments, and neutron scattering data are used to investigate ion pairing and clustering in a series of GdmSCN aqueous solutions. The MD simulations reproduce the major features of neutron scattering experimental data very well. Although no information about ion pairing or clustering can be obtained from the neutron scattering data, MD calculations clearly demonstrate that substantial amounts of ion pairs and small ion clusters (subnanometers to a few nanometers) do exist in the solutions of concentrations 0.5 M*, 3 M*, and 5 M* (M* denotes mole of GdmSCN per 55.55 mole of water). Vibrational relaxation experiments suggest that significant amounts of ion pairs form in the solutions. Experiments measuring the resonant energy transfers among the thiocyanate anions in the solutions suggest that the ions form clusters and in the clusters the average anion distance is 5.6 Å (5.4 Å) in the 3 M* (5 M*) Gdm-DSCN/D2O solution.
authors.affiliation: †State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 Liaoning, China.|§University of the Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Yuneng
authors.initials: Y
authors.lastname: Shen
authors.affiliation: ∥Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, China.
authors.forename: Tianmin
authors.initials: T
authors.lastname: Wu
authors.affiliation: †State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 Liaoning, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Jiang
authors.affiliation: †State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 Liaoning, China.
authors.forename: Ganghua
authors.initials: G
authors.lastname: Deng
authors.affiliation: ‡Department of Chemistry, Rice University, Houston, Texas 77005, United States.
authors.forename: Jiebo
authors.initials: J
authors.lastname: Li
authors.affiliation: ‡Department of Chemistry, Rice University, Houston, Texas 77005, United States.
authors.forename: Hailong
authors.initials: H
authors.lastname: Chen
authors.affiliation: ‡Department of Chemistry, Rice University, Houston, Texas 77005, United States.
authors.forename: Xunmin
authors.initials: X
authors.lastname: Guo
authors.affiliation: †State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 Liaoning, China.|⊥School of Physics and Electronic Technology, Liaoning Normal University, Dalian 116029, China.
authors.forename: Chuanqi
authors.initials: C
authors.lastname: Ge
authors.affiliation: †State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 Liaoning, China.
authors.forename: Yajing
authors.initials: Y
authors.lastname: Chen
authors.affiliation: †State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 Liaoning, China.
authors.forename: Jieya
authors.initials: J
authors.lastname: Hong
authors.affiliation: †State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 Liaoning, China.
authors.forename: Xueming
authors.initials: X
authors.lastname: Yang
authors.affiliation: †State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 Liaoning, China.
authors.forename: Kaijun
authors.initials: K
authors.lastname: Yuan
authors.affiliation: †State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of the Chemical Physics, Chinese Academy of Sciences, Dalian, 116023 Liaoning, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Zhuang
authors.affiliation: ‡Department of Chemistry, Rice University, Houston, Texas 77005, United States.
authors.forename: Junrong
authors.initials: J
authors.lastname: Zheng