Energy-structure relationships for microscopic solvation of anions in water clusters

Abstract

Articles you may be interested inElectronic structures and water reactivity of mixed metal sulfide cluster anions Coexistence of solvated electron and benzene-centered valence anion in the negatively charged benzenewater clusters J. Chem. Phys. 138, 014310 (2013); 10.1063/1.4773398 Effect of polarizability of halide anions on the ionic solvation in water clusters A collisional approach for the study of electron solvation in water and ammonia clusters and autodetachment of solvated molecular anions AIP Conf. Proc. 298, 528 (1994); 10.1063/1.45413 Photoelectron spectroscopy of iodine anion solvated in water clusters J. Chem. Phys. 95, 9416 (1991);In this paper we present a quantum-mechanical study of anions in water clusters, X-(H 2 0)n (X=Cl, Br, I, and n= 1-6). Molecular orbital calculations at the self-consistent field (SCF) level and at the second-order MQSller-Plesset (MP2) level were performed using extended basis sets. Full structural optimization was conducted at the MP2 level for n = 1 and at the SCF level for n=2-6. The energies and charge distribution of X-(H 2 0) were calculated at the MP2level, while the energies of the X-(H 2 0)n (n=2-6) clusters were calculated at the MP2level using the SCF optimized geometry. Calculations of total and sequential enthalpies of hydration and for the vertical ionization potentials were conducted for X-(H 2 0), the hydrogen bonded and linear isomers of X-(H 2 0h, the pyramidal structure of X-(H 2 0)3' and the interior and surface isomers of X-(H 2 0)n' n=4-6. The calculated hydration enthalpies account well for their experimental size dependence for n = 1-6. However, the isomer specificity of the hydration enthalpies is reflected by a small energy difference (<'>= 1-5 kcal mol-I) between the surface and interior isomers at a fixed n, precluding the assignment of structural isomers on the basis of ground-state energetics. The cluster size dependence and isomer specificity of the calculated vertical ionization potentials in conjunction with experimental data provide a diagnostic tool for the structural assignment of isomers and for the distinction between surface and interior structures. The central prediction emerging from the structure-energetic relations based on cluster size dependence and isomer specificity of vertical ionization potentials, is the prevalence of surface structures for Cl-(H 2 0)n (n=2-6), Br-(H 2 0)n (n=2-6), and I-(H 2 0)n (n=2-5), while a "transition" from surface to interior structure may be exhibited for I-(H 2 0)6'

Polarization and charge transfer in the hydration of chloride ions

“…65 To study these effects with our QM/MM model, we calculated the charge on the chloride ion using both the ChelpG and the QTAIM methods. Both approaches have been shown to be relatively accurate methods for the calculation of the amount of intermolecular electron transfer.…”

Study of the stabilization energies of halide-water clusters: An application of first-principles interaction potentials based on a polarizable and flexible model

“…1 which shows how clusters having different structures present similar values of E stab (n) and vice versa. What is more, there is no connection between the interaction energy of the ionic cluster ͑given in 24,25 who find evidences about a prevalent isomer of ͓X(H 2 O) n ͔ Ϫ clusters comparing the experimental E stab (n) and those obtained from ab initio calculations on minimum structures. Nevertheless, these authors work on minima structures at 0 K and limit their study only to a few conformers.…”

“…The analysis of this figure provides information of the size dependence on vertical ionization, a fact that has already been observed. 14,15,[23][24][25] The associated uncertainties of the E stab (n) for the larger ͓I(H 2 O) n ͔ Ϫ clusters is included in Fig. 2.…”

“…22 Although some authors 17,20,21,24 demonstrate that the use of Koopmans' theorem to compute ionization potentials of bare anions and ͓X(H 2 O) n ͔ Ϫ clusters overestimates the results by 0.4 -0.5 eV, its use to get ionization potential differences is suitable [23][24][25] because almost the same error exists in both systems.…”

“…Kim and co-workers [17][18][19][20][21] work, among other properties, on the ab initio prediction of the stabilization energies of ͓X(H 2 O) n ͔ Ϫ clusters (XϵF, Cl, Br, and I, nϭ1 -6) by both calculating the interaction energies difference between the ionic and the neutral cluster and using the Koopmans' theorem. 22 Combariza et al [23][24][25] carry out an ab initio study of the chloride-, bromide-, and iodide-water clusters to establish which are the prevalent isomers in gas phase. They used the agreement between stabilization energies obtained from the Koopman's theorem and binding enthalpies with the experimental data.…”