materials modeling on parallel computers

For realistic modeling of materials, a molecular-dynamics (MD) algorithm is developed based on multiresolutions in both space and time. Materials of interest are characterized by the long-range Coulomb, steric and charge-dipole interactions as well as three-body covalent potentials. The long-range Coulomb interaction is computed with the fast multipole method. For bulk systems with periodic boundary conditions, infinite summation over repeated image charges is carried out with the reduced cell multipole method. Short- and medium-range non-Coulombic interactions are computed with the multiple time-step approach. A separable tensor decomposition scheme is used to compute three-body potentials. For a 4.2 million-particle Si02 system, one MD step takes only 4.8 seconds on the 512-node Intel Touchstone Delta machine and 10.3 seconds on 64 nodes of an IBM SP1 system. The constant-grain parallel efficiency of the program is ~ ‘ = 0.92 and the communication overhead is 8 % on the Delta machine. On the SP1 system, ~ ‘ = 0.91 and communication overhead is 7%. 1