  The two-dimensional barrier passage is studied in the framework of Langevin
statistical reactive dynamics. The optimal incident angle for a particle
diffusing in the dissipative non-orthogonal environment with various strengths
of coupling between the two degrees of freedom is systematically calculated.
The optimal diffusion path of the particle in a non-Ohmic damping system is
revealed to have a probability to return to the potential valley under the
combined influence of the off-diagonal system tensors.
