UnitfulAtomic

This package extends the Unitful.jl package to facilitate working with atomic units.

This package provides three functions that enable easy conversion from and to Hartree atomic units:

• aunit(x) returns the appropriate atomic unit for x, where x can be a Unitful.Quantity, Unitful.Units, or Unitful.Dimensions:

  julia> aunit(2.3u"cm")
  a₀
  
  julia> aunit(u"T")
  ħ a₀^-2 e^-1

• auconvert can be used to convert from and to atomic units. It has two methods:
  • auconvert(x::Unitful.Quantity) converts a quantity to the appropriate atomic unit:

    julia> auconvert(13.6u"eV")
    0.499790781587053 Eₕ
    
    julia> auconvert(20u"nm")
    377.94522492515404 a₀

  • auconvert(u::Unitful.Units, x::Number) interprets x as a quantity in atomic units and converts it to the unit u:

    julia> auconvert(u"eV", 1)  # convert 1 Eₕ to eV
    27.211386246088992 eV
    
    julia> auconvert(u"m", 1)   # convert 1 a₀ to m
    5.29177210903e-11 m

• austrip(x::Unitful.Quantity) converts a quantity to the appropriate atomic unit and then strips the units. This is equivalent to Unitful.ustrip(auconvert(x)):

  julia> austrip(13.6u"eV")
  0.499790781587053
  
  julia> austrip(20u"nm")
  377.94522492515404

The package defines the following atomic units (suffixed with _au), from which all other atomic units are derived:

• me_au (printed as mₑ): the electron rest mass.
• e_au (printed as e): the elementary charge.
• ħ_au (printed as ħ): the reduced Planck constant.
• k_au (printed as k): the Boltzmann constant.
• a0_au (printed as a₀): the Bohr radius. The alias bohr can be used instead of a0_au.
• Eh_au (printed as Eₕ): the Hartree energy. The alias hartree can be used instead of Eh_au.

Furthermore, this package defines some units that are not atomic units, but are common in atomic physics:

• Ry: the Rydberg energy Ry = h*c*R∞ = Eₕ/2, see Rydberg constant.
• μ_N: the nuclear magneton.