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Constants

Available Constants

Physical constants are available directly after importing the package. No initialization is required.

julia> using AtomicAndPhysicalConstants
julia> C_LIGHT
2.99792458e8

Fundamental Constants

All constants are available as module-level constants:

Speed and Universal Constants

  • C_LIGHT: Speed of light [m/s]
  • H_PLANCK: Planck constant [eV⋅s]
  • H_BAR: Reduced Planck constant [eV⋅s]
  • E_CHARGE: Elementary charge [C]
  • FINE_STRUCTURE: Fine structure constant (dimensionless)
  • AVOGADRO: Avogadro constant [mol⁻¹]

Electromagnetic Constants

  • EPS_0: Permittivity of free space [F/m]
  • MU_0: Permeability of free space [N/A²]

Classical Radii

  • R_ELECTRON: Classical electron radius [m]
  • R_PROTON: Classical proton radius [m]

Particle Masses

All masses are in [eV/c²]:

  • M_ELECTRON: Electron mass
  • M_PROTON: Proton mass
  • M_NEUTRON: Neutron mass
  • M_MUON: Muon mass
  • M_PION_0: Neutral pion mass
  • M_PION_CHARGED: Charged pion mass
  • M_DEUTERON: Deuteron mass
  • M_HELION: Helion (³He nucleus) mass

Magnetic Moments

All magnetic moments are in [eV/T]:

  • MU_ELECTRON: Electron magnetic moment
  • MU_PROTON: Proton magnetic moment
  • MU_NEUTRON: Neutron magnetic moment
  • MU_MUON: Muon magnetic moment
  • MU_DEUTERON: Deuteron magnetic moment
  • MU_HELION: Helion magnetic moment
  • MU_TRITON: Triton magnetic moment

g-factors

All g-factors are dimensionless:

  • G_ELECTRON: Electron g-factor
  • G_PROTON: Proton g-factor
  • G_NEUTRON: Neutron g-factor
  • G_MUON: Muon g-factor
  • G_DEUTERON: Deuteron g-factor
  • G_HELION: Helion g-factor
  • G_TRITON: Triton g-factor

Magnetic Moment Anomalies

Dimensionless anomalies:

  • ANOMALY_ELECTRON: Electron magnetic moment anomaly
  • ANOMALY_MUON: Muon magnetic moment anomaly

Unit Conversions

  • KG_PER_AMU: Kilograms per atomic mass unit [kg/amu]
  • EV_PER_AMU: Electronvolts per atomic mass unit [eV/amu]
  • J_PER_EV: Joules per electronvolt [J/eV]

Release Information

  • RELEASE_YEAR: CODATA release year (2022)

Examples

using AtomicAndPhysicalConstants

# Physical constants
println("Speed of light: ", C_LIGHT, " m/s")
println("Electron mass: ", M_ELECTRON, " eV/c²")
println("Planck constant: ", H_PLANCK, " eV⋅s")
println("Fine structure constant: ", FINE_STRUCTURE)

# Unit conversions
println("1 amu = ", EV_PER_AMU, " eV/c²")
println("1 eV = ", J_PER_EV, " J")

Data Sources

All constants and species data are sourced from CODATA 2022 (Committee on Data of the International Science Council), the most recent internationally recommended values for fundamental physical constants.