- B -- Bohr radius, atomic unit of length, equal to
$0.52917721067\ \mathring{\mathrm A}$ or 0.52917721067 × 10 − 10 m -- [NISTCUU_B]- Eh -- Hartree, atomic unit of energy, equal to 4.35974465 J -- [NISTCUU_Eh]
- me -- Electron mass, atomic unit of mass, equal to 9.10938356 × 10 − 31 kg -- [NISTCUU_me]
- Ta -- Atomic time unit, equal to 2.4188843265 × 10 − 17 s -- [NISTCUU_Ta]
- cyc -- Numerical value of
$2\pi\ \left(\frac{\mathrm{cyc}}{2\pi}=1\right)$ , serving to convert angular frequencies into cyclic frequencies.- u -- unified atomic mass unit; equal to 1822.8885 me [NISTCUU_me_u] or 1.660539040 × 10 − 27 kg [NISTCUU_u_kg].