[en] The method of optimized expansions of the basis has been applied to the calculation of the dynamic polarizability of molecules in a Gaussian basis. The question of the form of the functions expanding the original basis has been examined in detail. A program has been compiled, and calculations are carried out for the molecules H₂⁺, H₂, He₂⁺⁺, and HeH⁺. The results show good agreement with the data obtained by other authors. It has been concluded that the method examined can be applied to large molecules

No abstract available

[en] An important step in variational calculations of excited state (ES) energies is the choice of a test function orthogonal to wave functions which describe the lower-lying states of the same symmetry. We describe an attempt to calculate the ES energy in the single-determinant approximation, but with the Roothaan basis tuned to the corresponding ES. The problem reduces to minimization of the energy functional with respect to nonlinear parameters of the basis set,with an additional condition that the states be orthogonal