TCBG Seminar

Long Time Step MD Simulations using Split Integration Symplectic Method

Dusanka Janezic
National Institute of Chemistry

Monday, July 13, 1998
3:00 pm (CT)
3269 Beckman Institute


An explicit Split Integration Symplectic Method (SISM) for molecular dynamics (MD) simulations is described. The method is based on splitting of the total Hamiltonian of the system into a harmonic part an the remaining part in such a way that both parts can be efficiently computed. The Hamilton equations of motion are then solved using the second order generalized leapfrog integration scheme in which the harmonic part is treated analytically by the normal mode analysis which is carried out only once, at the beginning of the calculation. The proposed method requires only one force evaluation per integration step, the computation cost per integration step is approximately the same as that of the standard leapfrog-Verlet method, but allows longer integration step than can be used by other methods of the same order. The method was applied to MD simulations of the system of linear chain molecules of the form H-(-C=C-)2-H. The simulation results show that the method posses long term stability and the ability to use long time steps.

Tea and coffee will be served in R3151 Beckman Institute at 2:15pm.

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