Quadrupole moment and a proton halo structure in ¹⁷F (I^π = 5/2⁺)

The quadrupole moment of light nuclei F-17 in the ground state (I-pi = 5/2(+)) is measured by the beta-NMR method. The effective charge of the last proton in a d(5/2) orbit for F-17 is extracted from the measured quadrupole moment Q(F-17) divided by the quadrupole moment Q(sp) calculated with a single particle model. A proton effective charge of e(p)(eff) = 1.12 +/- 0.07e is obtained, which is in agreement with that given by a particle-vibration coupling model calculation within the experimental error. The present value of the proton effective charge is strong evidence for the existence of a proton skin in F-17 (I-pi = 5/2(+)).