ISOTOPE SHIFTS IN ZR-91 FROM OPTOGALVANIC SATURATION SPECTROSCOPY

We present experimental values of the **9**0Zr-**9**1Zr isotope shift for seven lines in the spectral range of the Rhodamine 6G obtained with POLINEX and Intermodulated Saturation Optogalvanic spectroscopic techniques. The accuracy of our results, better than 20%, is indeed very good considering the small isotope shifts involved (of the order of 100 MHz). These results indicate that the addition of one neutron outside the closed, N equals 50, core of **9**0Zr results in line shifts which are consistent with the presence of an odd-even staggering effect.