A new formulation of the theory of quantum mechanical multichannel scattering for three-body collinear systems is proposed. It is shown that for this simple case, the principle of quantum determinism in the general case breaks down, and we have a micro-irreversible quantum mechanics. The first principle calculations of the quantum chaos (wave chaos) were pursued on the example of an elementary chemical reaction Li + (FH) → (LiFH)* → (LiF) + H.