Efficient hybrid algorithm for the dynamic creation of wormlike chains in solutions, brushes, melts and glasses

We present an algorithm for the creation and relaxation of large, dense or diluted homogeneous many particle systems made of wormlike, finite extendable, semiflexible multibead chains and - optionally - solvent, particles, which repulse each other. The key feature is its efficiency, its output has been proven to serve as an excellent basis for any subsequent off-lattice computer simulation. The application allows us to choose (i) the bead number density or packing fraction, temperature, chain length, system size; concentration, (ii) the interaction potentials, hence the local features such as bond length and bending rigidity of the chains, and (iii) the degree of pre-relaxation, parametrized and expressed through a minimum intermolecular distance. The monodisperse polymers are represented by chains of monomer coordinates in 3D space. During the dynamical two-step process of sample creation the initially (Monte Carlo step 1) predicted global characteristics of the molecular conformations remain as unaffected as possible (during molecular dynamics step 2) and the potential energy and the entropy production are relaxing towards their minima. The potentials, the distribution of bond lengths, the integration time step and temperature are smoothly controlled during the creation/relaxation process until they finally approach their prescribed or physical values. The quality of the algorithm is by its nature independent of concentration, system size or degree of polymerization; the computational speed is quite independent of the latter quantity and linear in the system size. Chains tethered to a surface (dry polymer brushes) can be generated; as well. We provide a benchmark table. (C) 1999 Elsevier Science B.V.