Analysis of the experimental pressure-temperature behavior in the isotropic-nematic transition of PAP, 5CB, MBBA and EBBA using the HERSW model in conjunction with the IPCM model. Influence of the molecular volume. Eduardo García-Sánchez, Luis H. Mendoza-Huizar, Irery A. Sustaita, Uriel Ramírez-García and Francisco Alvarado. Brazilian Journal of Physics, 45, pp- 258-263, 2015. Print ISSN 0103-9733, Online ISSN 1678-4448.DOI: 10.1007/s13538-014-0295-6
In this work, we have analyzed the experimental pressure-temperature behavior at the isotropic-nematic phase transition of the liquid crystals PAP, 5CB, MBBA, and EBBA at 1 atm by using the HERSW Convex Peg model in conjunction with the IPCM model. We have calculated the molecular volume values for the hard and attractive cores from theoretical quantum calculations at the PM3, PM6, B3LYP/6-311++G(d,p)//PM6, and M06/6-311++G(d,p)//PM6 levels of theory. The results suggest that the best theoretical prediction of the experimental pressure-temperature behavior is obtained when the molecular volume is evaluated at the DFT level.