  We report the results of intensive numerical calculations for four atomic
H2+H2 energy transfer collision. A parallel computing technique based on
LAM/MPI functions is used. In this algorithm, the data is distributed to the
processors according to the value of the momentum quantum number J and its
projection M. Most of the work is local to each processor. The topology of the
data communication is a simple star. Timings are given and the scaling of the
algorithm is discussed. Two different recently published potential energy
surfaces for the H2-H2 system are applied. New results obtained for the state
resolved excitation-deexcitation cross sections and rates valuable for
astrophysical applications are presented. Finally, more sophisticated
extensions of the parallel code are discussed.
