Deformed even–even nuclei Barium isotopes with quadrupole–octupole deformations are investigated on the basis of a collective model.The model describes energy levels of the yrast band with alternating parity in the neutron-rich~(140;142;144;146;148)Ba.The structure of the alternating parity bands is examined by odd–even (△I=1) staggering diagrams.An analytical method of the collective model is proposed for the calculation of E2 transition probabilities in alternating spectra of the nuclei~(140;142;144;146)Ba. Deformed even-even nuclei Barium isotopes with quadrupole-octupole deformations are investigated on the basis of a collective model. The model describes energy levels of the yrast band with alternating parity in the neutron-rich ~ (140; 142; 144; 146; 148 ) Ba. The structure of the alternating parity bands is examined by odd-even (ΔI = 1) staggering diagrams. An analytical method of the collective model is proposed for the calculation of E2 transition probabilities in alternating spectra of the nuclei ~ (140 ; 142; 144; 146) Ba.