Precision measurement of the electric quadrupole moment of 31Al and determination of the effective proton charge in the sd-shell

M. De Rydt, G. Neyens, K. Asahi, D. L. Balabanski, J. M. Daugas, M. Depuydt, L. Gaudefroy, S. Grévy, Y. Hasama, Y. Ichikawa, P. Morel, T. Nagatomo, T. Otsuka, L. Perrot, K. Shimada, C. Stödel, J. C. Thomas, H. Ueno, Y. Utsuno, W. VanderheijdenN. Vermeulen, P. Vingerhoets, A. Yoshimi

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


The electric quadrupole coupling constant of the 31Al ground state is measured to be νQ = | frac(e Q Vz z, h) | = 2196 (21)   kHz using two different β-NMR (Nuclear Magnetic Resonance) techniques. For the first time, a direct comparison is made between the continuous rf technique and the adiabatic fast passage method. The obtained coupling constants of both methods are in excellent agreement with each other and a precise value for the quadrupole moment of 31Al has been deduced: | Q (31Al) | = 134.0 (16)   mb. Comparison of this value with large-scale shell-model calculations in the sd and sdpf valence spaces suggests that the 31Al ground state is dominated by normal sd-shell configurations with a possible small contribution of intruder states. The obtained value for | Q (31Al) | and a compilation of measured quadrupole moments of odd-Z even-N isotopes in comparison with shell-model calculations shows that the proton effective charge ep = 1.1 e provides a much better description of the nuclear properties in the sd-shell than the adopted value ep = 1.3 e.

Original languageEnglish
Pages (from-to)344-349
Number of pages6
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Issue number4
Publication statusPublished - Jul 27 2009
Externally publishedYes


  • Al
  • Electric quadrupole moment
  • Island of inversion
  • Shell model
  • β Nuclear Magnetic Resonance (β-NMR)

ASJC Scopus subject areas

  • Nuclear and High Energy Physics


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