Non-additivity in water-ion-water interactions

Clementi, E.; Kistenmacher, H.; Kołos, W.; Romano, S.

doi:10.1007/bf00549424

Cited by 128 publications

(59 citation statements)

References 12 publications

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“…In studies of monovalent ions such as Li I , [32] Na I , [38] and K I , [38] it has been reported that additional three-body potentials remarkably improve the agreement with experimental data. For divalent metal ions such as Mg II and Ca II[39±41] it has been shown that three-body effects are even more dominant and consequently crucial to obtain reliable hydration numbers and equilibrium distances for the first hydration shell.…”

Section: Introductionmentioning

confidence: 85%

New Insights into the Jahn–Teller Effect through ab initio Quantum‐Mechanical/Molecular‐Mechanical Molecular Dynamics Simulations of Cu^II in Water

Schwenk

Rode

2003

ChemPhysChem

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The CuII hydration shell structure has been studied by means of classical molecular dynamics (MD) simulations including three-body corrections and hybrid quantum-mechanical/molecular-mechanical (QM/MM) molecular dynamics (MD) simulations at the Hartree-Fock level. The copper(II) ion is found to be six-fold coordinated and [Cu(H2O)6]2+ exhibits a distorted octahedral structure. The QM/MM MD approach reproduces correctly the experimentally observed Jahn-Teller effect but exhibits faster inversions (< 200 fs) and a more complex behaviour than expected from experimental data. The dynamic Jahn-Teller effect causes the high lability of [Cu(H2O)6]2+ with a ligand-exchange rate constant some orders or magnitude higher than its neighbouring ions NiII and ZnII. Nevertheless, no first-shell water exchange occurred during a 30-ps simulation. The structure of the hydrated ion is discussed in terms of radial distribution functions, coordination numbers, and various angular distributions and the dynamical properties as librational and vibrational motions and reorientational times were evaluated, which lead to detailed information about the first hydration shell. Second-shell water-exchange processes could be observed within the simulation time scale and yielded a mean ligand residence time of approximelty 20 ps.

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Section: Introductionmentioning

confidence: 85%

New Insights into the Jahn–Teller Effect through ab initio Quantum‐Mechanical/Molecular‐Mechanical Molecular Dynamics Simulations of Cu^II in Water

Schwenk

Rode

2003

ChemPhysChem

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“…According to recent studies [7,8] the threebody interaction energy is dominated by the corresponding long-range induction term = -2 a,(Efl-A E2-' ) , (8) which is estimated in our approach using the same a values as in the @rLE two-body term. …”

Section: )mentioning

confidence: 99%

Crystal structure studies using ab-initio potential functions from partitioned ab-initio MODPOT/VRDDO SCF energy calculations. I. N2 and CO2 test cases. II. Nitromethane, CH3NO2

Sokalski

Roszak

Lowrey

et al. 2009

Int. J. Quantum Chem.

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Several years ago we embarked on a project to calculate optimal crystal-packing and crystalstructure parameters based on potential functions from energy-partitioned ab-initio intermolecular SCF calculations plus calculations of dispersion energy contributions. Our approach, aimed at evaluating the intermolecular interactions, such as in polymer propagation and in molecular crystals, and at analyzing the optimal crystal packing, is based on nonempirical ab-inirio calculations for smaller molecular aggregates (monomers, dimers, trimers, etc.), partitioning the total SCF interaction energies into the .different components, and then fitting these components individually to functional forms or when necessary recalculating or estimating explicitly for certain interaction components for each different unit cell dimension change. We derived and implemented a complete program, including higher order terms and special features necessary only for calculations on crystals. We also derived and implemented a complete CRYSTAL program which, given the crystal symmetry, allows us to vary and optimize the crystal-structure parameters. We carried out test crystal optimization calculations on N2 and on C02 both to check out the entire CRYSTAL program package and to explore the extensive programs written for various ab-initio based methods for calculating reliable intermolecular interactions. We investigated such aspects as the comparison of the various intermolecular interaction terms calculated from the potential functions compared with those calculated by ob-initio wave functions. We also investigated for the CRYSTAL program how many surrounding unit cells had to be included for energy convergence. We investigated the crystal CH~NOZ. We calculated the intermolecular interactions at more than 50 geometries, partitioned the interaction energies, and fit these to functional forms. The agreement of our calculated unit cell dimensions with experiment was excellent, within I to 2.8%. Furthermore, our method fits the partitioned ~E X F results to atom-class-atom-class potential functions, which enables a general library of such potential functions to be built up for the molecular classes of interest.

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“…The dispersion correction can be added easily to the two-body potentials by using perturbation-derived relations if the interaction energies are obtained in the one-electron approximation [20]. The induction effects are the main nonadditivity corrections needed for three-or many-body systems, and can be approximated by perturbation techniques [21]. In model 2, it is very important to define a set of atom-atom potentials which can be used to describe many different molecules; that is, the potential must be a "transferable" potential.…”

Section: Linked Set Of Models To Simulate Complex Chemical Systemsmentioning

confidence: 99%

Theoretical and computational chemistry of complex systems: Solvation of DNA and proteins

Clementi¹,

Corongiu²,

Gratarola³

et al. 2009

Int. J. Quantum Chem.

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As is known, atomic and very small molecular systems can be realistically simulated by quantum mechanical models. In complex chemical systems, however, the natural parameters are not only electronic density and energy but also entropy, temperature, and time. To approach this description we use a hierarchy of theoretical models. In model I , the system is considered as an ensemble of fixed nuclei and electrons-the standard quantum chemical approach. However. our definition of model I is broader, since it includes aspects of solid-state physics. In model 2, the system is considered as an ensemble of atoms (or ions) and atom-pair potentials are obtained using data from model 1. In model 3, the phase space is scanned either for the generalized coordinates (Monte Carlo) or for both space and momentum coordinates (molecular dynamics). In model 4 (presently not considered) the fluid dynamical equations are solved making use of coefficients and parameters obtained from the previous models. Both theoretical and computational improvements are needed at each level in order to reach a sufficiently realistic simulation for complex systems. We have summarized some recent progress obtained for models 1 and 2 related to new methods for molecular computations and studies on three-body effects and energy band computations in DNA-related polymers. We have considered as examples of a complex chemical system the structure of water surrounding DNA (with counterions) and enzymes. Our results from model 3 include the first determination of the position of the Li+, Na+, and K+ counterions in B and Z DNA at room temperature at high relative humidity, and hydration studies on enzymes including variations due to the solvent pH.

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Non-additivity in water-ion-water interactions

Cited by 128 publications

References 12 publications

New Insights into the Jahn–Teller Effect through ab initio Quantum‐Mechanical/Molecular‐Mechanical Molecular Dynamics Simulations of Cu^II in Water

New Insights into the Jahn–Teller Effect through ab initio Quantum‐Mechanical/Molecular‐Mechanical Molecular Dynamics Simulations of Cu^II in Water

Crystal structure studies using ab-initio potential functions from partitioned ab-initio MODPOT/VRDDO SCF energy calculations. I. N2 and CO2 test cases. II. Nitromethane, CH3NO2

Theoretical and computational chemistry of complex systems: Solvation of DNA and proteins

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Non-additivity in water-ion-water interactions

Cited by 128 publications

References 12 publications

New Insights into the Jahn–Teller Effect through ab initio Quantum‐Mechanical/Molecular‐Mechanical Molecular Dynamics Simulations of CuII in Water

New Insights into the Jahn–Teller Effect through ab initio Quantum‐Mechanical/Molecular‐Mechanical Molecular Dynamics Simulations of CuII in Water

Crystal structure studies using ab-initio potential functions from partitioned ab-initio MODPOT/VRDDO SCF energy calculations. I. N2 and CO2 test cases. II. Nitromethane, CH3NO2

Theoretical and computational chemistry of complex systems: Solvation of DNA and proteins

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Product

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New Insights into the Jahn–Teller Effect through ab initio Quantum‐Mechanical/Molecular‐Mechanical Molecular Dynamics Simulations of Cu^II in Water

New Insights into the Jahn–Teller Effect through ab initio Quantum‐Mechanical/Molecular‐Mechanical Molecular Dynamics Simulations of Cu^II in Water