A relationship between the Avogadro’s number NA and the transition frequency of the caesium 133 atom ΔνCs
At the 26th meeting of the General Conference on Weights and Measures (CGPM) held on 13‐16 November 2018 at Versailles, France, the new International System of Units (SI) was established. Following the CGPM’s decision, the new SI units were established based upon a set of seven defining constants. This set of constants is the most fundamental feature in the definition of the entire system of units. What is truly remarkable about the new SI is the fact that all measurement units, except the amount of substance mole and Avogadro’s number NA , are defined based on the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom <mml:math display="inline"> <mml:msub> <mml:mrow> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:mi>ν</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">Cs</mml:mi> </mml:mrow> </mml:msub> </mml:math> equal to 9 192 631 770 Hz. This article, based on dimensional analysis, presents the possibility of connecting the Avogadro’s number NA and the mole, to the transition frequency <mml:math display="inline"> <mml:msub> <mml:mrow> <mml:mo>Δν</mml:mo> </mml:mrow> <mml:mrow> <mml:mtext>Cs</mml:mtext> </mml:mrow> </mml:msub> </mml:math> .