Giacomo Prampolini1. 1. Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via Risorgimento 35, I-56126 Pisa, Italy.
Abstract
A novel multisite interaction potential, suitable for computer simulations of complex materials as liquid crystals or polymers, is proposed and parametrized. Its validation is achieved through Monte Carlo numerical experiments at constant temperature and pressure, performed on the p-n-phenyls series and a typical mesogenic molecule (5CB). The model is constructed by connecting an array of anisotropic Gay-Berne sites and a collection of isotropic Lennard-Jones sites. The former mimics the rigid planar six-membered rings of the molecule, while the latter represents the flexible chain, if present. Such intermolecular potential, coupled with an intramolecular part to account for molecular flexibility, is parametrized from ab initio information only, obtained through the recently proposed Fragmentation-Reconstruction Method (FRM). Computer simulations are performed on all systems by exploring phase behavior at several temperatures and by comparing the resulting thermodynamic and structural properties with the relevant experimental data. Despite the simplicity of the present models, the good agreement with the experimental measures suggests the possibility of adopting such hybrid potentials for those systems with a large number of atoms, where high computational cost does not allow the use of more accurate atomistic potentials.
A novel multisite interaction potential, suitable for computer simulations of complex materials as liquid crystals or polymers, is proposed and parametrized. Its validation is achieved through Monte Carlo numerical experiments at constant temperature and pressure, performed on the p-n-n class="Chemical">phenyls series anpan>d a typical mesogenpan>ic molecule (5CB). The model is conpan>structed by conpan>nectinpan>g anpan> array of anpan>isotropic Gay-Bernpan>e sites anpan>d a collectionpan> of isotropic Lenpan>nard-Jonpan>es sites. The former mimics the rigid planpan>ar six-membered rinpan>gs of the molecule, while the latter represenpan>ts the flexible chainpan>, if presenpan>t. Such inpan>termolecular potenpan>tial, coupled with anpan> inpan>tramolecular part to accounpan>t for molecular flexibility, is parametrized from ab inpan>itio inpan>formationpan> onpan>ly, obtainpan>ed through the recenpan>tly proposed Fragmenpan>tationpan>-Reconpan>structionpan> Method (FRM). Computer simulationpan>s are performed onpan> all systems by explorinpan>g phase behavior at several temperatures anpan>d by comparinpan>g the resultinpan>g thermodynpan>amic anpan>d structural properties with the relevanpan>t experimenpan>tal data. Despite the simplicity of the presenpan>t models, the good agreemenpan>t with the experimenpan>tal measures suggests the possibility of adoptinpan>g such hybrid potenpan>tials for those systems with a large number of atoms, where high computationpan>al cost does not allow the use of more accurate atomistic potenpan>tials.