目から鱗のマススペクトロメトリー第6回「amu」 : amuの基準は^<12>Cではありません [in Japanese] Comments on Usage of the Unit Symbol "amu" [in Japanese]
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The unified atomic mass unit (unit symbol: u) is a non-SI unit of mass defined as one twelfth the mass of a single <sup>12</sup>C atom in its ground state. This definition was agreed upon by both the International Union of Pure and Applied Physics and the International Union of Pure and Applied Chemistry in early 1960s to resolve a longstanding difference between two scales of atomic mass unit. The term "atomic mass unit" (unit symbol: amu) has been used to a unit of mass defined as one sixteenth the mass of a single atom <sup>16</sup>O [<i>m</i>(<sup>16</sup>O)=16 amu] in physics, or as one sixteenth the isotope-averaged atomic mass (equivalent to the atomic weight) of oxygen [<i>A</i><sub>r</sub>(O)=16 amu] in chemistry.<br>It is a common mistake to use the deprecated term "atomic mass unit" and the deprecated unit symbol "amu" for the unit of mass defined as one twelfth the mass of single atom <sup>12</sup>C.
- J. Mass Spectrom. Soc. Jpn.
J. Mass Spectrom. Soc. Jpn. 54(6), 259-271, 2006-12-01
The Mass Spectrometry Society of Japan