الملخص

Abstract The energy of the first exited state , and , , and for 132-126Ba even-even isotopes are compared with the standard values for the three limits, the vibration U(5), gamma-soft O(6) and the rotational SU(3). The back-bending curve and the relation between as a function of ( E-GOS) are drawn for these isotopes to have more information about their properties. Calculation of the energy of different states along the yrast region has been done using the standard relations for each limit, U(5), O(6) and SU(3) and a comparison with the experimental data show that they have the O(6) property for low-lying states and a O(6) – U(5) property for the high states, except for 132 Ba that shows a O(6) – U(5) property for all these states with different values of parameters along the yrast region. The interacting boson model IBM-1 has been used to calculate the energy of different states along the yrast region applying a suitable limit for each isotopes. A program with MATLAB 6.5 has been built for this purpose. Agood agreement with the experimental data was obtained.