Modeling small hydronium–water clusters

Hodges, Matthew P.; Stone, Anthony J.

doi:10.1063/1.478580

Cited by 62 publications

(63 citation statements)

References 47 publications

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“…Equation (11) also covers the interaction of induced molecular dipoles, since the difference between the charge transferred from the ion onto a molecule and perturbations in the charge distribution of the electronic shell of the molecule in the field of the ion becomes rather conditional at contact distances.…”

Section: Simulation Of the Cluster H 3 O + (H 2 O) Nmentioning

confidence: 99%

“…The electrostatic intermolecular repulsion induced by charge transfer is included as the energy of interacting dipoles with a varied parameter c (0 < c < 1) that represents a correction in the anisotropy of interactions, associated with the nonpoint character of the dipoles [Eq. (11)]. U WW TR = S 777 3 3(1 3 c) 777777 .…”

Section: Simulation Of the Cluster H 3 O + (H 2 O) Nmentioning

confidence: 99%

“…One should also account for fluctuations of the pattern of energy levels, that facilitate thermally initiated quantum transitions. In the ground quantum state, first water molecules add to the H 3 O + ion from the three-proton side [11]. In the ground quantum state, there is no energy minimum near the oxygen atom of the ion, required for stabilization of the attached water molecule, as the electrostatic repulsion of the excess positive charge of the ion wipes out the binding effect of the dipole3dipole interaction with water molecules from the oxygen side.…”

Section: Problem Of Description Of Interactions In Ion3mentioning

confidence: 99%

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Computer simulation of molecular complexes H3O+(H2O)n under conditions of thermal fluctuations: I. Interactions in the system

Шевкунов

2004

Russ J Gen Chem

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The simplest pair model of intermolecular interactions fails to reproduce known experimental free energy and entropy of hydration of H 3 O + ions in water vapor. A fit to experiment is attained only when covalent bonds and nonpair interactions, which are of particular importance at contact distances from the ion, are taken into account. An interaction model was constructed, which allows the experimental free energies of cluster formation to be reproduced to fractions of k B T by the Monte3Carlo method. Numerical values of interaction parameters were obtained by fitting simulated results to refined experimental data. Problem of description of interactions in ion3water clusters. Though the boundary between clusters and molecules is rather conventional, it is a common practice to associate formation of molecules with formation of chemical bonds. A distinctive feature of such interactions is their nonpair nature whose extreme manifestation is the effect of saturation of chemical bonds according to atomic valence. The nature of interactions (pair or nonpair) might serve as a criterion in attributing a certain molecular complex to clusters or molecules. However, this scheme, too, has its disadvantages. Nonpair interactions also can be of essential importance in typical clusters, especially in clusters formed in a strong electric field of an ion. Quantum-chemical calculations of the energies of various molecular configurations were fulfilled by Kistenmacher et al. [1] for clusters with 2310 water molecules on the Li + , Na + , K + , F 3 , and Cl 3 ions. The numerical results were approximated by analytic functions that were then used in statistical calculations at finite temperature. The nonpair interaction is most contributed by water3ion3water terms. Water3water3 water interactions are negligibly small. Three-body interactions make up~10% of the energy of a system (tens k B T, where k B is Boltzmann constant and T is absolute temperature), and four-body interactions make up 132%. The contributions from many-body interactions are approximately proportional to the amount of water3ion3water triplets in the first coordination shell. Interactions with the ion contribute most to cluster energy.There are two basic techniques for constructing model intermolecular potentials: quantum-chemical calculations by the Hartree3Fock self-consistent field (SCF) method with subsequent corrections for electron correlations and a reconstruction of the potential from measurable thermal and structural properties of real substances. Inclusion of nonpair interactions involves multiple solution of the Schroedinger equation for a great number of molecular configurations followed by approximation of the numerical results by multidimensional functional relationships. Sequential fulfillment of this program requires huge computing expenditures. Systematic investigations aimed at the reconstruction of intermolecular potentials from thermal and structural properties of water had been initiated in early 1970s [2310]. A series of models of intermolecul...

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Section: Simulation Of the Cluster H 3 O + (H 2 O) Nmentioning

confidence: 99%

Section: Simulation Of the Cluster H 3 O + (H 2 O) Nmentioning

confidence: 99%

Section: Problem Of Description Of Interactions In Ion3mentioning

confidence: 99%

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Computer simulation of molecular complexes H3O+(H2O)n under conditions of thermal fluctuations: I. Interactions in the system

Шевкунов

2004

Russ J Gen Chem

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“…In the case of locally stable configurations, the problem of identification of an ion in a cluster is simplified, as in the absence of fluctuations it is always possible to separate one oxygen ion linked by valence bonds with three hydrogen atoms on the background of remaining ions forming only two such bonds. According to the calculations [8], first water molecules add to a minimum-energy hydroxonium ion from the side of protons. Three water molecules form three hydrogen bonds with the ion, in which the latter plays the role of proton donor.…”

mentioning

confidence: 99%

“…Configurations corresponding to local minima of the energy of a [frozen] H 3 O + (H 2 O) n cluster were examined in [8]. The calculation was fulfilled by quantum-chemical methods in the approximation of heavy nuclei.…”

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Computer simulation of molecular complexes H3O+(H2O)n under conditions of thermal fluctuations: II. Work of formation and structure

Шевкунов

2004

Russ J Gen Chem

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The free energy, entropy, and work of formation of H 3 O + (H 2 O) n clusters (n = 1!27) in water vapor (300 K) were calculated by the Monte Carlo method. Binary correlation functions were calculated. The calculations are based on the nonpair interaction model presented in the previous publication. The hydration shell of the ion is thermally stable in the size range under study. Nonpair interactions exert an essential effect on the structure of the cluster. Fitting the cluster behavior to its experimental thermodynamic characteristics shows that the excess charge of the ion is spatially delocalized at room temperature, and the role of hydrogen bonds is strengthened on this background. Clusters formed on electric charges have such a fundamental characteristic as transition size. The transition size is independent of vapor pressure and demarcates two qualitatively different mechanisms of holding molecules in a cluster. A change in the holding mode is reflected on the mechanism of vapor nucleation.Method. Monte Carlo calculations with the nonpair potential recovered in the previous work [1] from experimental free energy and entropy of cluster formation, were carried out in large canonical mVT and bicanonical [234] statistical ensembles. The latter ensemble was used to calculate the cluster free energy. Comparison of the calculated data showed that effects associated with the nonequivalence of the ensembles are weak and thus were not considered in this publication.One of the input parameters of the large canonical assemble simulating material contact of a cluster with vapor is chemical molecular potential m. For convenience in comparison with experimental data, numerical results are given in terms of vapor pressure p. Recalculation of m into p was carried out by the formulas for the ideal gas of rigid rotors [5]. A cluster was placed in a spherical cavity of radius R 1 nm with rigid walls. An ion H 3 O + was fixed in the center of the cavity (which was simultaneously the coordinate origin) in such a way that its oxygen atom was in the point x = 0, y = 0, z = 0. As the vapor pressure increased, the equilibrium size of the cluster increased and, once a certain critical value had been exceeded, it passed in an avalanche growth restricted only by walls of the cavity. The size of the cavity was selected so ÄÄÄÄÄÄÄÄÄÄÄÄ 1 For communication I, see [1]. that a clearance in some angstrom filled with vapor was preserved between the cluster surface and the walls in the stability mode. The average number of molecules in this clearance is negligibly small in comparison with the number of molecules in the cluster. The initial configuration for each Markov chain was created independently by randomly throwing molecules in the system with the probabilities of the large canonical assemble, and subsequent thermalization. To calculate equilibrium averages, Markov chains with a multiple reserve of statistical dataset were generated. The length of Markov chains was 5.4 0 10 8 steps for each point. The frequency ratios of various types of ...

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Unique Hydrogen‐Bonded Complex of Hydronium and Hydroxide Ions

Stapf

Seichter

Mazik

2015

Chemistry A European J

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H3 O(+) and OH(-) , formed by the self-ionization of two coordinating water molecules during the crystal growing of a host molecule [1,3,5-tris(hydroxymethyl)2,4,6-triethylbenzene (1)], could be effectively stabilized by hydrogen-bonding interactions with the preorganized hydroxy groups of three molecules of 1. The binding motifs observed in the complex (1)3 ⋅H3 O(+) ⋅HO(-) show remarkable similarity to those postulated for the hydrated hydronium and hydroxide ion complexes, which play important roles in various chemical, biological, and atmospheric processes, but their molecular structures are still not fully understood and remain a subject of intensive research.

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Modeling small hydronium–water clusters

Cited by 62 publications

References 47 publications

Computer simulation of molecular complexes H3O+(H2O)n under conditions of thermal fluctuations: I. Interactions in the system

Computer simulation of molecular complexes H3O+(H2O)n under conditions of thermal fluctuations: I. Interactions in the system

Computer simulation of molecular complexes H3O+(H2O)n under conditions of thermal fluctuations: II. Work of formation and structure

Unique Hydrogen‐Bonded Complex of Hydronium and Hydroxide Ions

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