  A high-accuracy mass measurement of 7Li was performed with the Smiletrap
Penning trap mass spectrometer via a cyclotron frequency comparison of Li3+ and
H2+. A new atomic mass value of 7Li has been determined to be
7.016,003,425,6,(45)u with a relative uncertainty of 0.63 ppb. It has uncovered
a discrepancy as large as 14 sigma (1.1 micro u) deviation relative to the
literature value given in the Atomic-Mass Evaluation AME 2003. The importance
of the improved and revised 7Li mass value, for calibration purposes in
nuclear-charge radii and atomic mass measurements of the neutron halos 9Li and
11Li, is discussed.
