Units of Measure

Atomic Units

  • \(\mathrm B\) – Bohr radius, atomic unit of length, equal to \(0.52917721067\ \mathring{\mathrm A}\) or \(0.52917721067\times 10^{-10}\ \mathrm m\)[NISTCUU_B]
  • \(\mathrm{E_h}\) – Hartree, atomic unit of energy, equal to \(4.35974465~\mathrm J\)[NISTCUU_Eh]
  • \(\mathrm{m_e}\) – Electron mass, atomic unit of mass, equal to \(9.10938356\times 10^{-31} \ \mathrm{kg}\)[NISTCUU_me]
  • \(\mathrm{T_a}\) – Atomic time unit, equal to \(2.4188843265\times 10^{-17}\ \mathrm s\)[NISTCUU_Ta]

Other Units

  • \(\mathrm{cyc}\) – Numerical value of \(2\pi\ \left(\frac{\mathrm{cyc}}{2\pi}=1\right)\), serving to convert angular frequencies into cyclic frequencies.
  • \(\mathrm{u}\) – unified atomic mass unit; equal to \(1822.8885\ \mathrm{m_e}\) [NISTCUU_me_u] or \(1.660539040\times 10^{-27}\ \mathrm{kg}\) [NISTCUU_u_kg].