Nuclear Charge Radius of Li-9, Li-11: Halo Neutron: the influence of   Halo Neutrons
  The nuclear charge radius of Li-11 has been determined for the first time by high precision laser spectroscopy. On-line measurements at TRIUMF-ISAC yielded a Li-7 - Li-11 isotope shift (IS) of 25101.23(13) MHz for the Doppler-free 2s - 3s transition. IS precision for all other bound Li isotopes was also improved. Differences from calculated mass-based IS yield values for change in charge radius along the isotope chain. The charge radius decreases monotonically from Li-6 to Li-9, and then increases from 2.217(35) fm to 2.467(37) fm for Li-11. This is compared to various models, and it is found that a combination of halo neutron correlation and intrinsic core excitation best reproduces the experimental results. 
R. S\'anchez, W. N\"ortersh\"auser, G. Ewald, D. Albers, J. Behr, P.   Bricault, B. A. Bushaw, A. Dax, J. Dilling, M. Dombsk...