Running sums for 2νββ-decay matrix elements within the QRPA with account for deformation

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The 2νββ-decay running sums for ⁷⁶Ge and ¹⁵⁰Nd nuclei are calculated within a QRPA approach with account for deformation. A realistic nucleon-nucleon residual interaction based on the Brueckner G matrix (for the Bonn CD force) is used. The influence of different model parameters on the functional behavior of the running sums is studied. It is found that the parameter gpp renormalizing the G matrix in the QRPA particle-particle channel is responsible for a qualitative change in behavior of the running sums at higher excitation energies. For realistic values of gpp a significant negative contribution to the total 2νββ-decay matrix element is found to come from the energy region of the giant Gamow-Teller resonance. This behavior agrees with the results of other authors.