Estimation of thermodynamic parameters in 3.Om and 3O.Om liquid crystalline compounds

Abstract

Thermodynamic parameters such as Moelwyn–Hughes parameter (C1), reduced volume (V~), reduced compressibility (β), isochoric temperature coefficient of internal pressure (X), Sharma parameter (S0), Huggin's parameter (F), Grüneisenparameter(Γp),isothermalmicroscopic Grüneisen parameter(Γ),fraction freevolume (f) and acoustical parameters like isothermal (K′), isobaric (K), isochoric (K″)acousticalparameters,isothermal Grüneisen parameter (Γith), isobaric Grüneisen parameter (Γiba), isochoric Grüneisen parameter (Γich), reduced Bulk modulus (B~), isothermal Anderson–Grüneisen parameter (δ) and magnitude of repulsive exponent (n) are estimated from thermal expansion coefficient, α obtained from density variation with temperature, ρ in liquid crystalline N-(p-n-propyl/propyloxybenzylidene)-p-n-alkoxy anilines, 3.Om and 3O.Om with m = 6, 7 and 8. In addition to these, the parameters like molecular free length (Lf), molecular radius (mr)andnonlinearity parameter, (B/A) are alsoevaluated. The variation of all these parametersarestudiedboth withthetemperatureinanindividualcompoundandwiththechainlengthinahomologousseries.Further,theresultsagreewith the body of the data available.