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Algorithm for reduction of boundary-value problems in multistep adiabatic approximation

The adiabatic approximation is well-known method for effective study of few-body systems in molecular, atomic and nuclear physics, using the idea of separation of "fast" and "slow" variables. The generalization of the standard adiabatic ansatz for the case of multi-channel wave function when all variables treated dynamically is presented. For this reason we are introducing the step-by-step averaging methods in order to eliminate consequently from faster to slower variables. We present a symbolic-numerical algorithm for reduction of multistep adiabatic equations, corresponding to the MultiStep Generalization of Kantorovich Method, for solving multidimensional boundary-value problems by finite element method. An application of the algorithm to calculation of the ground and first exited states of a Helium atom is given.