TITLE

Monte Carlo simulation of acetonitrile clusters [CH3CN]N, N=2–256: Melting transitions and even/odd character of small clusters (N=2–9), heat capacities, density profiles, fractal dimension, intracluster dimerization, and dipole orientation

AUTHOR(S)
Wright, D.; El-Shall, M. Samy
PUB. DATE
March 1994
SOURCE
Journal of Chemical Physics;3/1/1994, Vol. 100 Issue 5, p3791
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
The thermodynamic and structural properties of acetonitrile clusters [CH3CN]N, N=2–15, 20, 30, 60, 128, and 256 have been investigated using Monte Carlo simulation. Interactions in the small clusters (N≤9) are dominated by antiparallel pairing of the molecular dipoles. The simulations reveal rigid fluid (melting) transitions with a remarkable even–odd alternation in the transition temperatures for the N=2–9 clusters. The higher melting temperatures of the even-N clusters arise as consequences of the antiparallel paired dipoles which provide favorable electrostatic interactions. Even–odd alternation has also been observed in the configurational energies and heat capacities and the percentage of molecules possessing an antiparallel nearest neighbor. These observations are consistent with the fact that Coulomb potential terms dominate the interaction energies in clusters with N<12. The average density in clusters with N>=60 is fairly well represented by the bulk liquid density. Order parameters characterizing dipole orientation indicate that the molecular dipoles tend to lie flat on the cluster surface for N≥30. Significant dimerization within the clusters suggests evaporation of molecules via dimers and an enhancement of evaporative loss over condensation and this may explain the slower nucleation rates observed for acetonitrile compared to the predictions of the classical nucleation theory.
ACCESSION #
7618003

 

Related Articles

  • Free energy from constrained molecular dynamics. Sprik, Michiel; Ciccotti, Giovanni // Journal of Chemical Physics;11/8/1998, Vol. 109 Issue 18, p7737 

    Examines the development of thermodynamic integration for the free energy difference of many-body systems. Imposition of mechanical constraint on the corresponding reaction coordinate; Computation for the mean force potential and transmission coefficient; Use of standard Monte Carlo techniques...

  • Thermodynamic limit of the excess internal energy of the fluid phase of a one-component... Caillol, J. M. // Journal of Chemical Physics;10/8/1999, Vol. 111 Issue 14, p6538 

    Reports on a Monte Carlo study of thermodynamic limit of the excess internal energy of the fluid phase of a one-component plasma. Use of the standard Metropolis algorithm to build Markov chains in the canonical ensemble; Decimal logarithm of the maximum relative error on the pair potential for...

  • First-order transition of a homopolymer chain with Lennard-Jones potential. Liang, Haojun; Haojun Liang; Chen, Hanning; Hanning Chen // Journal of Chemical Physics;9/8/2000, Vol. 113 Issue 10 

    The thermodynamics of a homopolymer chain with the Lennard-Jones (LJ) potential was studied by the multicanonical Monte Carlo method. The results confirm there indeed exists a liquid-solid-like first-order transition at lower temperatures for a free-joint chain, revealing that the transition is...

  • A new technique for grand canonical Monte Carlo simulation: Application in a hard-disk system. Caliri, A.; da Silva, M. A. A.; Mokross, B. J. // Journal of Chemical Physics;11/15/1989, Vol. 91 Issue 10, p6328 

    We present a new Monte Carlo approach which is capable to reduce significantly the two-phase coexistence region by constraining the system to remain fairly homogeneous in the transition region. This is achieved by introducing the chemical potential as an extra intensive thermodynamic variable in...

  • Thermodynamics of finite magnetic two-isomer systems. Borrmann, Peter; Stamerjohans, Heinrich; Hill, Eberhard R.; Jund, Philippe; Seong Gon Kim; Tomanek, David // Journal of Chemical Physics;12/15/1999, Vol. 111 Issue 23, p10689 

    Discusses the use of Monte Carlo simulations to investigate the thermodynamical behavior of aggregates consiting of few superparamagentic particles in a colloidal suspension. Potential energy surface of the classical two-isomer system with a stable and a metastable ring and chain configuration;...

  • Isotopic shift in the melting curve of helium: A path integral Monte Carlo study. Barrat, Jean-Louis; Loubeyre, Paul; Klein, Michael L. // Journal of Chemical Physics;5/15/1989, Vol. 90 Issue 10, p5644 

    The path integral Monte Carlo method is used to estimate the difference in the melting pressures of 4He and 3He. Thermodynamic and structural properties of both isotopes are also computed using an effective pair potential for the interaction between helium atoms. At low temperature, calculations...

  • Monte Carlo simulations at constant chemical potential and pressure. Ray, John R.; Wolf, Ralph J. // Journal of Chemical Physics;2/1/1993, Vol. 98 Issue 3, p2263 

    The usual way of carrying out Monte Carlo simulations of open systems is by using the grand canonical ensemble. In the grand canonical (TVμ) ensemble a system of fixed volume V is in contact with a temperature reservoir having temperature T, and a particle reservoir having chemical potential...

  • Monte Carlo study of mixed electrolytes in the primitive model. Besˇter, M.; Vlachy, V. // Journal of Chemical Physics;5/15/1992, Vol. 96 Issue 10, p7656 

    Canonical Monte Carlo results are presented for mixtures of primitive model electrolytes with a common ion. Both symmetric mixtures, where the ions differ only in size, and charge asymmetric mixtures were studied for ionic strengths ranging from 0.003 to 1.0 M. The hypernetted chain (HNC)...

  • Influence of the range of attractive forces on vapor/liquid phase coexistence. Shukla, K.; Rajagopalan, Raj // Journal of Chemical Physics;12/15/1994, Vol. 101 Issue 12, p11077 

    The influence of the range of interparticle attractions on vapor/liquid coexistence in spherically symmetric systems has been investigated by mapping the pair potential on to the adhesive-hard-sphere model. Comparisons of our analytical predictions with recent Gibbs-Ensemble Monte Carlo...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics