Producción Científica Profesorado

Predicting the Phase Diagram of a Liquid Crystal Using the Convex Peg Model and the Semiempirical PM3 Method



Mendoza Huizar, Luis Humberto

2002

Predicting the phase diagram of a liquid crystal using the Convex Peg model and the semi-empirical PM3 method. Eduardo García-Sánchez, Antonio Martínez-Richa, José Antonio Villegas-Gasca, Luis Humberto Mendoza-Huizar, and Alejandro Gil-Villegas. DOI: 10.1021/jp021453o


Abstract


A molecular theory to determine thermodynamic properties of isotropic and nematic phases of liquid crystals is proposed, based on a convex peg model and semiempirical PM3 (Parametrized Method 3) calculations. The Helmholtz-free energy of the molecular system, a convex hard core within an encircling spherical square-well (SW) potential, is obtained from a second-order perturbation theory for SW nonspherical particles, combined with the Parsons decoupling approximation of the translational and rotational degrees of freedom, and a long-range approximation for the evaluation of the perturbation terms. The theory is applied to predict the phase diagram and isotropic?nematic transition of p-azoxyanisole. To do this, an estimation of the volume of a p-azoxyanisole molecule is derived from a minimum-energy geometry, using PM3 calculations; the volume obtained is mapped into a hard ellipsoid revolution volume of a Convex Peg molecule. A very good agreement in the prediction of the thermodynamic properties is obtained when compared with experimental data.



Producto de Investigación




Artículos relacionados

Revisión de variables de diseño y condiciones de operación en la electrocoagulación

Quantum chemical study of the electrochemical reduction of the [Co(H2O)6]2+ and [Co(NH3)5(H2O)]2+ io...

Kinetics of Polypyrrole Films Doped with Sulphate Ions Electrodeposited Over Graphite - Epoxy Resin ...

Zinc Electrodeposition from Chloride Solutions onto Glassy Carbon Electrode

A theoretical quantum study on the distribution of electrophilic and nucleophilic active sites on Ag...

A Voltammetric Study Of The Underpotential Deposition Of Cobalt Onto A Glassy Carbon Electrode

Theoretical and Experimental Study of Cobalt Nucleation and Growth onto Gold Substrate with Differen...

The role of temperature in copper electrocrystallization in ammoniachloride solutions

A theoretical quantum study on the distribution of electrophilic and nucleophilic active sites on th...

Synthesis of Zn compounds derived from 1H-benzimidazol-2-ylmethanamine