Static Quadrupole Moment of the First 2+ States of the Even Tin Nuclei

Measurements of the relative thick-target yields of γ rays deexciting the 2+ first excited states in 112,116,118,120,122,124Sn, following Coulomb excitation by α particles and ¹⁶O ions, have been interpreted in terms of the relative static quadrupole moments of these states. The absolute static quadrupole moment of the 2+ state in ¹²⁰Sn was determined to be +(0.09 ±{} 0.10) b. With this value it was then possible to obtain the absolute static quadrupole moments for the 2+ state in the other even tin nuclei. The resulting values are closer to the vibrational-model prediction (static quadrupole moment of zero) than to values predicted by the rotational model. A set of absolute B(E2,0→2) values was also obtained with assigned errors between 2 and 3%.