@article{kenkare_smith_hall_khan_1998, title={Discontinuous molecular dynamics studies of end-linked polymer networks}, volume={31}, ISSN={["0024-9297"]}, DOI={10.1021/ma9801422}, abstractNote={Discontinuous molecular dynamics simulations are used to study the structure and relaxation of large, off-lattice, near-perfect, tri- and tetrafunctional polymer networks at a packing fraction of 0.43. The networks are constructed by end-linking freely jointed, tangent hard-sphere chains ranging in length from N = 20 to N = 150 and are then relaxed for 5−20 billion collisions. The simulation trajectories are used to calculate the radius of gyration and end-to-end distance of the network chains, the static structure factor of the cross-links, the mean-squared displacement of the cross-links and chain inner segments, the intermediate scattering function of the chains, and the elastic modulus of the network. The structure and properties of the networks are shown to depend heavily on the manner in which the network is initially constructed. The dynamics of the network cross-links and chain inner segments are similar to those of melt chains at short times and show evidence of spatial localization at long times...}, number={17}, journal={MACROMOLECULES}, author={Kenkare, NR and Smith, SW and Hall, CK and Khan, SA}, year={1998}, month={Aug}, pages={5861–5879} }
@article{smith_hall_freeman_1997, title={Molecular dynamics for polymeric fluids using discontinuous potentials}, volume={134}, ISSN={["0021-9991"]}, DOI={10.1006/jcph.1996.5510}, abstractNote={Molecular dynamics simulation techniques for systems interacting with discontinuous potentials are discussed. Optimization and efficiency techniques are summarized for performing discontinuous molecular dynamics on serial computers with direct application to polymer-like fluids. Comparisons are presented for two algorithms: (1) single-event scheduling, and (2) multiple-event scheduling. The single-event scheduling algorithm is approximately 75% faster than the multiple-event scheduling algorithm for molecular fluids but yields equivalent performance for atomic fluids. For the single-event scheduling method, a combination of link lists and neighbor lists are used when searching for possible particle interactions. The combination of efficiency techniques permits multibillion time step simulations for relatively large systems on desktop workstations. Both discontinuous molecular dynamics codes for single and multiple-event scheduling algorithms are available on the Internet. The utility of the method is demonstrated for entangled chains, tethered chains, and heteronuclear chain mixtures.}, number={1}, journal={JOURNAL OF COMPUTATIONAL PHYSICS}, author={Smith, SW and Hall, CK and Freeman, BD}, year={1997}, month={Jun}, pages={16–30} }
@article{smith_freeman_hall_1997, title={Pressure-dependent photon correlation spectroscopic investigation of poly(propylene oxide) near the glass transition}, volume={30}, ISSN={["0024-9297"]}, DOI={10.1021/ma960408+}, abstractNote={The effect of pressure on structural relaxations in poly(propylene oxide) (PPO; MW = 4000) near the glass transition has been determined using photon correlation spectroscopy. Experimental results are reported for pressures ranging from 2.5 to 3.9 kbar at 253 K. The structural relaxation exhibits two distinct processes separated by ∼3 orders of magnitude in time. This observation is consistent with results of dielectric relaxation studies of PPO. The faster relaxation is associated with local segmental motions important in the glass-rubber transition. The mean relaxation time for the faster process exhibits an exponential dependence on pressure.}, number={7}, journal={MACROMOLECULES}, author={Smith, SW and Freeman, BD and Hall, CK}, year={1997}, month={Apr}, pages={2052–2057} }