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ABSTRACT: In order to understand the microsolvation of LiI and CsI in water and provide information about the dependence of solvation processes on different ions, we investigated the LiI(H2O)n- and CsI(H2O)n- (n=0-6) clusters using photoelectron spectroscopy. The structures of these clusters and their corresponding neutrals were investigated with ab initio calculations and confirmed by comparing with the photoelectron spectroscopy experiments. Our studies show that the structural evolutions of LiI(H2O)n and CsI(H2O)n clusters are very different. The Li-I distance in LiI(H2O)n- increases abruptly at n=3, whereas the abrupt elongation of the Li-I distance in neutral LiI(H2O)n occurs at n=5. In contrast to the LiI(H2O)n- clusters, the Cs-I distance in CsI(H2O)n- increases significantly at n=3, reaches a maximum at n=4, and decreases again as n increases further. There is no abrupt change of Cs-I distance in neutral CsI(H2O)n as n increases from 0 to 6. Water molecules interact strongly with the Li ion, consequently, water molecule(s) can insert in between the Li+ and I- ion pair. In contrast, five or six water molecules are not enough to induce obvious separation of Cs+-I- ion pair since the Cs-water interaction is relatively weak compared to the Li-water interaction. Our work has shown that the structural variation and microsolvation in MI(H2O)n clusters are determined by the delicate balance between ion-ion, ion-water, and water-water interactions, which may have significant implications for the general understanding of salt effects in water solution.
Journal of the American Chemical Society 02/2013; · 9.91 Impact Factor
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Chemical Physics Letters 08/2012; 545:21-25. · 2.34 Impact Factor
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ABSTRACT: We investigated the reactions between cobalt-oxides and water molecules using photoelectron spectroscopy and density functional calculations. It has been confirmed by both experimental observation and theoretical calculations that dihydroxide anions, Co(m)(OH)(2)(-) (m = 1-3), were formed when Co(m)O(-) clusters interact with the first water molecule. Addition of more water molecules produced solvated dihydroxide anions, Co(m)(OH)(2)(H(2)O)(n)(-) (m = 1-3). Hydrated dihydroxide anions, Co(m)(OH)(2)(H(2)O)(n)(-), are more stable than their corresponding hydrated metal-oxide anions, Co(m)O(H(2)O)(n+1)(-).
The Journal of chemical physics 10/2011; 135(13):134307. · 3.09 Impact Factor
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ABSTRACT: We investigated the reactions between cobalt-oxides and water molecules using photoelectron spectroscopy and density functional calculations. It has been confirmed by both experimental observation and theoretical calculations that dihydroxide anions, Com(OH)2− (m = 1–3), were formed when ComO− clusters interact with the first water molecule. Addition of more water molecules produced solvated dihydroxide anions, Com(OH)2(H2O)n− (m = 1–3). Hydrated dihydroxide anions, Com(OH)2(H2O)n−, are more stable than their corresponding hydrated metal-oxide anions, ComO(H2O)n+1−.
The Journal of Chemical Physics 10/2011; 135(13):134307-134307-5. · 3.33 Impact Factor
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ABSTRACT: We investigated the microscopic solvation of NaBO(2) in water by conducting photoelectron spectroscopy and ab initio studies on NaBO(2)(-)(H(2)O)(n) (n = 0-4) clusters. The vertical detachment energy (VDE) of NaBO(2)(-) is estimated to be 1.00 ± 0.08 eV. The photoelectron spectra of NaBO(2)(-)(H(2)O)(1) and NaBO(2)(-)(H(2)O)(2) are similar to that of bare NaBO(2)(-), except that their VDEs shift to higher electron binding energies (EBE). For the spectra of NaBO(2)(-)(H(2)O)(3) and NaBO(2)(-)(H(2)O)(4), a low EBE feature appears dramatically in addition to the features observed in the spectra of NaBO(2)(-)(H(2)O)(0-2). Our study shows that the water molecules mainly interact with the BO(2)(-) unit in NaBO(2)(-)(H(2)O)(1) and NaBO(2)(-)(H(2)O)(2) clusters to form Na-BO(2)(-)(H(2)O)(n) type structures, while in NaBO(2)(-)(H(2)O)(3) and NaBO(2)(-)(H(2)O)(4) clusters, the water molecules can interact strongly with the Na atom, therefore, the Na-BO(2)(-)(H(2)O)(n) and Na(H(2)O)(n)···BO(2)(-) types of structures coexist. That can be seen as an initial step of the transition from a contact ion pair (CIP) structure to a solvent-separated ion pair (SSIP) structure for the dissolution of NaBO(2).
Physical Chemistry Chemical Physics 09/2011; 13(35):15865-72. · 3.57 Impact Factor
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ABSTRACT: The Sc(3)O(6)(-) cluster anions were produced by laser ablation and studied by reaction with n-butane in a fast flow reactor and by photoelectron spectroscopy. The reactivity experiments indicated that one Sc(3)O(6)(-) cluster can activate two n-butane molecules consecutively with rate constants on the order of 10(-10) cm(3) molecule(-1) s(-1) under near room-temperature conditions, suggesting that the even-electron system Sc(3)O(6)(-) has a highly reactive electronic structure. The photoelectron spectroscopy determined a high vertical detachment energy (VDE) of 5.63 ± 0.08 eV for the Sc(3)O(6)(-) cluster. Density functional computations indicated that the lowest energy isomer of Sc(3)O(6)(-) is an oxygen-centered biradical with a high VDE and is highly reactive toward n-butane, which is in good agreement with the experiments. The Sc(3)O(6)(-) cluster may serve as an ideal model system to provide insight into the real-life chemistry involved with the coupled O(-)˙···O(-)˙ dimers over the surfaces of metal oxide catalysts.
Physical Chemistry Chemical Physics 06/2011; 13(21):10084-90. · 3.57 Impact Factor
