Parallel wave-packet simulations of electron transmission through water

The dynamics of electron tunneling through water layers embedded between tw o metal plates is studied by electron wave-packet simulations. The tunnelin g flux is shown to increase by orders of magnitude due to resonances when t he thermal motion of the water nuclei is "frozen'' and transient molecular nanocavities dominate the tunneling mechanism. This enhancement is observed even when the energy width of the wave-packet is larger than the resonance width, and the transmission probability does not show resonance peaks as a function of the impact electron energy. The wave-packet simulations are ba sed on a parallel solution of the multidimensional time-dependent Schroding er equation, in which the N-dimensional Hilbert space is distributed into s ubspaces associated with an N-dimensional hypercube of processors. The prop agated wave function is fully distributed at all times and the computation rate can increase linearly with the number of processors. The significant a dvantage of the present algorithm over serial algorithms is in the ability to increase the size of the propagated wave-functions without increasing th e computation time by adding more processors. (C) 2000 American Institute o f Physics. [S0021-9606(00)51506-2].