Mixed quantum-classical molecular dynamics: Aspects of the multithreads algorithm

The mixed quantum-classical Liouville equation is derived from a semiclassi cal perspective starting from the full quantum Schrodinger equation. An asy mptotic numerical scheme for solving the equation is discussed which relies on propagating swarms of interacting "threads" which represent the density matrix or other observable. It is demonstrated that this "multithreads" me thod performs extremely well on simple one-dimensional model systems design ed to test nonadiabatic molecular dynamic methods, yielding essentially exa ct results for a variety of models. (C) 2000 American Institute of Physics. [S0021-9606(00)71441-3].