Microscopic description of octupole collective excitations near <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>N</mml:mi><mml:mo>=</mml:mo><mml:mn>56</mml:mn></mml:mrow></mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>N</mml:mi><mml:mo>=</mml:mo><mml:mn>88</mml:mn></mml:mrow></mml:math>

Octupole deformations and related collective excitations are analyzed using the framework of nuclear density functional theory. Axially-symmetric quadrupole-octupole constrained self-consistent mean-field (SCMF) calculations with a choice universal energy pairing interaction performed for Xe, Ba, Ce isotopes from proton-rich to neutron-rich regions, Se, Kr, Sr isotopes, in which enhanced octupole correlations expected occur. Low-energy positive- negative-parity spectra transition strengths computed by solving Hamiltonian, inertia parameters potential determined SCMF calculations. Octupole-deformed equilibrium states found surfaces Ba $N\approx 56$ 88. The evolution spectroscopic properties indicates regions corresponding Z\approx 56$, $Z\approx 88$ 34$. average $\beta_{30}$ deformation parameter its fluctuation exhibit signatures shape phase around $N=56$