Impact on reproducibility Proposed redefinition of SI base units

(



c


{\displaystyle c}

= speed of light,



α


{\displaystyle \alpha }

= fine-structure constant,




r

∞




{\displaystyle r_{\infty }}

= rydberg constant.)

it should noted relative atomic mass of electron ar(e) measured relative mass of carbon-12 atom (divided 12). when avogadro constant set in new si, atomic masses might measured in dalton (by fixing avogadro constant), instead of atomic mass units (by fixing mass of carbon-12), resulting in difference between values of relative atomic mass , atomic mass in units of dalton.

dalton

in 1993, international union of pure , applied chemistry (iupac) approved use of dalton alternative unified atomic mass unit qualification cgpm had not given approval. approval has since been given. following proposal redefine mole fixing value of avogadro s number, brian leonard of university of akron, writing in metrologia proposed dalton (da) redefined such na = (g/da) mol, unified atomic mass unit (mu) retain current definition based on mass of c, ceasing equal dalton. result in dalton , atomic mass unit potentially differing each other relative uncertainty of order of 10.

cite error: there <ref group=note> tags on page, references not show without {{reflist|group=note}} template (see page).