Level energy(keV) Spin & Parity ---------------------------------------- ground state 1/2+Mass (The Ame2012 atomic mass evaluation (II) by M.Wang, G.Audi, A.H.Wapstra, F.G.Kondev, M.MacCormick, X.Xu, and B.Pfeiffer Chinese Physics C36 p. 1603-2014, December 2012)
184.997600 ± 0.000087 (amu) [mass excess = -2236 ± 81 (keV) ] [These values were derived from systematical trend]Evaluated Data Libraries
Links to the libraries.