Measurement of quadrupole moment of the 134 keV level in Cs-131

The time differential as well as time integral perturbed angular correlatio ns of the 486-134 keV cascade in Cs-131 have been studied in a polycrystall ine BaSO4 powder source using a HPGe-BaF2 detector system. The fundamental quadrupole frequency for the 134 keV level has been found to be omega(0) (4 .4 +/- 0.4) x 10(7) rad/s. From a comparison of the quadrupole frequencies of this level and that of the 81 keV level in Cs-133, measured earlier in t he same crystalline environment of the source, the absolute value of the qu adrupole moment of the 134 keV level in Cs-131 has been found to be 0.022 /- 0.002 b. This value of the quadrupole moment is reported for the first t ime and compared with the value predicted theoretically within the unified nuclear model with intermediate coupling.