Molecular dynamics simulations of liquid crystal phases using atomistic potentials

Molecular dynamics simulations have been carried out for the liquid crystal molecule 4,4'-di-n-pentyl-bibicyclo[2.2.2]octane (5,5-BBCO). A united-atom model was employed with the central bicyclooctane groups in the core of 5,5-BBCO modelled as rigid units using a quaternion leapfrog algorithm in combination with bond length constraints, making use of the QSHAKE (er;tension to SHAKE) algorithm. Results are presented for the structure and :dynamics of (5,5-BBCO) at a series of state points in the range 200-500 K for sample sizes of 64 and 125 molecules, and run lengths of up to 12 ns. The growth of orientational order directly from the isotropic phase is found to be extremely slow, taking place over a period of 6-10 ns. This phase change is accompanied by major conformational changes in the molecules themselves.