On a variant of commutator estimates in spectral theory

For two orithree-particle Schrodinger operator $H$ thе positivity of $\operatorname{Re}((H-\lambda)f,Af)$ is used to construct $H$-smooth operators. Asymptotic completeness in the short-range case is proved. The absence of embedded eigenvalues is a byproduct of the method for two particle system.