Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
Effect Of External Electric Field On The Bulk And Interfacial Properties Of Weakly Dipolar Fluid In Slab-Shaped And Sphere-Shaped Systems, V.B. Warshavsky, Xiao Cheng Zeng
Effect Of External Electric Field On The Bulk And Interfacial Properties Of Weakly Dipolar Fluid In Slab-Shaped And Sphere-Shaped Systems, V.B. Warshavsky, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
The effect of a uniform electric field on the bulk and interfacial properties of a model dipolar fluid is investigated by using a modified mean-field density functional theory. Particular attention is given to the dependence of the vapor-liquid phase coexistence in a slab-shaped system on the direction of the electric field with respect to the slab surfaces, as well as in the sphere-shaped system on the surrounding dielectric permittivity. For planar vapor-liquid interfaces, the interfacial profiles of the orientation order parameters and components of the dielectric-permittivity tensor are calculated. Analytical expressions for these interfacial profiles and their dependence on the …
Coarse-Graining Description Of Solid Systems At Nonzero Temperature, Z.-B. Wu, Dennis J. Diestler, Ruqiang Feng, Xiao Cheng Zeng
Coarse-Graining Description Of Solid Systems At Nonzero Temperature, Z.-B. Wu, Dennis J. Diestler, Ruqiang Feng, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
The quasicontinuum (QC) technique, in which the atomic lattice of a solid is coarse-grained by overlaying it with a finite-element mesh, has been employed previously to treat the quasistatic evolution of defects in materials at zero temperature. It is extended here to nonzero temperature. A coarse-grained Hamiltonian is derived for the nodes of the mesh, which behave as quasiparticles whose interactions are mediated by the underlying (non-nodal) atoms constrained to move in unison with the nodes. Coarse-grained thermophysical properties are computed by means of the Monte Carlo (MC) method. This dynamically constrained QC MC procedure is applied to a simple …
Effect Of Polarizability Of Halide Anions On The Ionic Salvation In Water Clusters, S. Yoo, Y.A. Lei, Xiao Cheng Zeng
Effect Of Polarizability Of Halide Anions On The Ionic Salvation In Water Clusters, S. Yoo, Y.A. Lei, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
Molecular dynamics simulation has been performed to study the effect of the polarizabilities of model anions on the ionic solvation in water clusters. The primary focus is given to the surface versus interior solvation behavior of the anions. To this end, various combinations of polarizable/nonpolarizable water and anion models were considered. Using the nonpolarizable TIP4P water with polarizable Cl2 and Br2 models, the Cl2 is fully solvated inside the (H2O) 60 cluster, whereas the Br2 is partially solvated at the surface of the cluster. However, when the polarizability of the Br2 is turned …
Global Geometry Optimization Of Silicon Clusters Described By Three Empirical Potentials, S. Yoo, Xiao Cheng Zeng
Global Geometry Optimization Of Silicon Clusters Described By Three Empirical Potentials, S. Yoo, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
The “basic-hopping” global optimization technique developed by Wales and Doye is employed to study the global minima of silicon clusters Sin (3<nnnn=17, as opposed to n=19. For larger SW clusters (20<n n =20. In particular, the overall structural features of SW Si21, Si23, Si25, and Si28 are nearly identical to the MSW counterparts. With the SW Si21 as the starting structure, a geometric optimization at the B3LYP/6-31G(d) level of density-functional theory yields an isomer similar to the ground-stateisomer of Si21 reported by Pederson et …
Bulk And Interfacial Properties Of A Dipolar-Quadrupolar Fluid In A Uniform Electric Field: A Density-Functional Approach, V.B. Warshavsky, Xiao Cheng Zeng
Bulk And Interfacial Properties Of A Dipolar-Quadrupolar Fluid In A Uniform Electric Field: A Density-Functional Approach, V.B. Warshavsky, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
We have studied the bulk and interfacial properties of a dipolar-quadrupolar fluid based on an extended modified mean-field density-functional theory. Effects of a uniform electric field on the bulk and interfacial properties are also studied. Results of the coexisting vapor-liquid densities, interfacial profiles of the density and orientation order parameters, the surface tension, and their dependence on the temperature, magnitude of molecule dipole and quadrupole moment, and the applied field are obtained. In general, we find that the applied field increases the critical temperature, broadens the vapor-liquid coexistence curves, and reduces the surface tension. We also find that if the …
Ab Initio Studies Of Quasi-One-Dimensional Pentagon And Hexagon Ice Nanotubes, Jaeil Bai, C.-R. Su, R. D. Parra, Xiao Cheng Zeng, H. Tanaka, K. Koga, J.-M. Li
Ab Initio Studies Of Quasi-One-Dimensional Pentagon And Hexagon Ice Nanotubes, Jaeil Bai, C.-R. Su, R. D. Parra, Xiao Cheng Zeng, H. Tanaka, K. Koga, J.-M. Li
Xiao Cheng Zeng Publications
Ab initio plane-wave total-energy calcuation is carried out to study the relative stability of the quasi-one-dimensional (Q1D) pentagon and hexagon ice nanotubes. Electronic structure calculations indicate the two Q1D ice nanotubes have nearly the same band structures and energy bandgap as those of proton-ordered bulk ice Ih . Ab initio molecular-orbital and density-functional theory calculations, as well as three classical potential models of water, are also employed to investigate the relative stability of the pentagon and hexagon water clusters (H2O) 30, (H2O) 60 , and (H2O) 120 . Clusters of this kind …
Structures And Stabilities Of Small Silicon Clusters: Ab Initio Molecular-Orbital Calculations Of Si7–Si11, Xiaolei Zhu, Xiao Cheng Zeng
Structures And Stabilities Of Small Silicon Clusters: Ab Initio Molecular-Orbital Calculations Of Si7–Si11, Xiaolei Zhu, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
Ab initio all-electron molecular-orbital calculations have been carried out to study the structure and relative stability of small silicon clusters (Sin , n=7 – 11). A number of low-energy geometric isomers are optimized at the second-order Møller–Plesset (MP2) MP2/6-31G(d) level. Harmonic vibrational analysis has been performed to assure that the optimized geometries are stable. The total energies of stable isomers are computed at the coupled-cluster single and double substitutions (including triple excitations) [CCSD(T)] CCSD(T)/6-31G(d) level. The calculated binding energies per atom at both the MP2/6-31G(d) and CCSD(T)/6-31G(d) levels agree with …
Cooperative Effects In One-Dimensional Chains Of Three-Center Hydrogen Bonding Interactions, Ruben D. Parra, Satya S. Bulusu, Xiao Cheng Zeng
Cooperative Effects In One-Dimensional Chains Of Three-Center Hydrogen Bonding Interactions, Ruben D. Parra, Satya S. Bulusu, Xiao Cheng Zeng
Xiao Cheng Zeng Publications
Cooperative effects in a one-dimensional network of intermolecular bifurcated hydrogen bonding interactions are investigated by means of ab initio calculations. The trans–trans conformation of the diformamide molecule is used as a basic motif to model a chain of bifurcated H bonds. In this model system, the two proton–acceptor atoms belong to the same molecule. The one-dimensional network is modeled then by periodically stacking up to 12 molecules of the unit motif. Different indicators of H-bond strength such as energetic, structural, dielectric, vibrational frequencies, and isotropic chemicals shifts consistently show significant cooperative effects in the chains. The dissociation energy in the …