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Phase Behaviour Study of a Mesogen in a Solvent: Role of Molecular Rigidity and Configurational Entropy

P. Lakshmi Praveen


The phase behaviour of a nematogen 4’-n-pentyloxy-4-biphenylcarbonitrile (POBPCB) has been studied with respect to the translational and orientational motions. The charges of atoms and their dipole moments have been estimated by implementing the complete neglect differential overlap (CNDO/2) method. The long-range interactions have been analyzed using modified Rayleigh-Schrodinger Perturbation theory together with the multicentred-multipole expansion scheme. The “6-exp” potential function has been considered to study the short-range interactions. The minimum energy configurations obtained during the different modes of interactions have been taken as input to calculate the configurational probability using the Maxwell-Boltzmann in polar aprotic solvent i.e., Dimethylformamide (DMF) at room temperature (300 K) and nematic-isotropic transition temperature (340.5 K). A comparison between rigidity analysis and configurational entropy explains the nematic behaviour of the compound. 


4’-n-pentyloxy-4-biphenylcarbonitrile (POBPCB), molecular rigidity, configurational entropy, Dimethylformamide (DMF), Rayleigh-Schrodinger Perturbation theory

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