Erratum: Many-body effects in molecular dynamics simulations of Na+(H2O)n and Cl−(H2O)n clusters [J. Chem. Phys. 95, 1954 (1991)] (original) (raw)

Many-body effects in molecular dynamics simulations of Na+(H2O)n and Cl−(H2O)n clusters

The Journal of Chemical Physics, 1991

Many-body effects were examined in a series of molecular dynamics computer simulations on the ionic aqueous clusters Na+ (H,O), (n = 4,5,6,14) and Cl-(H,O), (n = 4,5,6,7,8,14). Two potential models were used in the simulations. In one model (TIP4P) the potential was pairwise additive, while in the second model (SPCE/POL) the many body effects were explicitly included through a self-consistent polarization routine. The two models produce equilibrium structures which are significantly different in energy and geometry. The SPCE/POL model consistently predicts energetically more stable products. In addition, for the anion cluster systems the SPCE/POL model places the Cl -on the surface of the water cluster.

On the formation of transient (Na19)2 and (Na20)2 cluster dimers from molecular dynamics simulations

Physics Letters A, 1994

By using &stance-dependent tight-binding molecular dynamics slmulaUons, we &scuss the posslbdmes to form (Na19)2 and (Na2o) 2 cluster &mers m sodmm cluster-cluster colhslons. In the case of Nal 9 + Na,9, we show that the formaUon of a prolate dlmer-llke (Nat9)2 may depend on the lmtml relative orientations of the colhdmg clusters A similar study for Na2o+Na2o does not seem to show the same dependence on the mlUal orientations in the formation of the (Na2o)2 cluster dlmer

Theoretical Study of Small (NaI) n Clusters

The Journal of Physical Chemistry B, 1997

A systematic theoretical study of stoichiometric clusters (N aI) n up to n = 15 is performed using the ab initio Perturbed-Ion (PI) model. The structures obtained are compared to previous pair potential results, and observed differences between (N aI) n clusters and previous ab initio results for other alkali halide clusters are discussed. (N aI) n clusters with n up to 15 do not show yet a marked preference for geometries which are fragments of the bulk lattice. Instead, stacks of hexagonal rings or more open structures are obtained as ground structures in clusters with n = 3, 6, 7, 9, 10, 12, 13 and 15, indicating that convergence to bulk structure is not achieved yet at this size range. Low lying isomers which are fragments of the crystal lattice exist, nevertheless, for those cases. The binding energies show that clusters with n = (4), 6, 9 and 12 molecules are specially stable. The binding energy has been decomposed in contributions which allow for an intuitive interpretation. Some electronic properties like ionization potentials and electronic energy levels are also studied.

The effects of electronic structure and charged state on thermodynamic properties: An ab initio molecular dynamics investigations on neutral and charged clusters of Na, Na, and Na

2008

In this paper we explore the effects of the electronic structure, the charge state, and the nature of energy distribution of isomers on the thermodynamic properties of sodium clusters. The focus of the work is to isolate the effects of these ingredients on thermodynamic behavior by choosing specific clusters. Toward this end we investigate Na 39 − , Na 40 , and Na 41 + , which are the electronic closed shell systems which differ in number of atoms and charge state. We also examine Na 39 , Na 39 + , Na 40 + , and Na 41 clusters having different charges of these clusters. Our density functional molecular dynamics simulations show that all electronic shell-closing clusters have similar melting temperature of Ϸ310 K. Remarkably, it is observed that an addition of even one electron to Na 39 increases the melting temperature by about 40 K and makes the specific heat curve sharper. All the cationic clusters show broadened specific heat curves.

Na+/K+.cntdot.(H2)1,2 clusters: binding energies from theory and experiment

The Journal of Physical Chemistry, 1994

Dissociation energies for H2 loss from Na+.(H2) 1.2 and K+.(H2) 1,2 clusters have been determined via temperaturedependent equilibrium measurements. DO =-M o o = 2.45 f 0.2 and 2.25 f 0.2 kcal/mol for Na+-H2 and HyNa+-H2, respectively, and 1.45 f 0.2 and 1.26 f 0.4 kcal/mol for K+-H2 and HyK+-H2, respectively. Also, a b initio calculations on Na+.H2 were carried out at the HF and MP2 levels with an extended basis set and compared with previous calculations on this system as well as with experiment. By extrapolating these purely electrostatic results to the first-row transition series, one can conclude that covalent interactions dominate the bonding in V+-H2 and Co+-H2 systems.