Rotational dynamics of a dipolar supercooled liquid

We study the rotational dynamics of a supercooled molecular liquid by means of molecular dynamics simulations. The system under investigation is composed of rigid diatomic molecules with an associate dipole moment. At room temperature, orientational correlations decrease rapidly with increasing distances. Upon cooling, angles between dipole moments of molecules within the first coordination shell decrease. As for the dynamical properties, rotational diffusion coefficients decrease with temperature at a smaller rate than translational diffusion coefficients do, and the critical temperature associated with the former is lower than the one corresponding to their translational counterparts. Translation and rotation about an inertial axis are uncorrelated, whereas some coupling between translation and dipole reorientation is obtained.