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PhysConst

A collection of fundamental physical constants in various unit systems for MATLAB.

Licensing

This software is licensed under the GNU General Public License (version 3).

Tested On

• MATLAB R2013b - R2018a

Syntax

v=Constant.NameOfConstant returns the value of the named constant in the default unit system. See the list of physical constant names. For examples:

• v=Constant.ElementaryCharge returns the value of the elementary charge, e;
• v=Constant.LightSpeed returns the value of the speed of light, c.

Default Unit System

By default, the values are returned in the SI units. To set a different unit system as default, do one of the following:

• Make a variable assignment: UnitSystem='UnitSystemCode';, where UnitSystemCode refers to the unit system to be used. See the list of unit system codes.
• Define an anonymous function: UnitSystem=@()'UnitSystemCode';.
• Create a function named UnitSystem in the current working directory or elsewhere. The function takes no input arguments and returns a string specifying the unit system code.

v=Constant.UnitSystemCode.NameOfConstant returns the value of the named constant in the specified unit system, regardless of the default unit system. For examples:

• v=Constant.SI.ElementaryCharge returns the value of the elementary charge, e, in the SI units (=1.602176565);
• v=Constant.P.LightSpeed returns the value of the speed of light, c, in the Planck units (=1).

Uncertainties

[v,u]=Constant.NameOfConstant and [v,u]=Constant.UnitSystemCode.NameOfConstant additionally return the uncertainty of the named constant.

List of Unit System Codes

• HA: Hartree Atomic Units
• P: Planck Units
• QCD: Quantum Chromodynamics Units
• RA: Rydberg Atomic Units
• S: Stoney Units
• SI: International System of Units

List of Physical Constant Names

• AtomicMass: atomic mass unit, m_u
• AvogadroNumber: Avogadro's number, N_A
• BohrMagneton: Bohr magneton, μ_B
• BohrRadius: Bohr radius, a₀
• Boltzmann: Boltzmann constant, k_B
• ConductanceQuantum: conductance quantum, G₀
• Coulomb: Coulomb constant, k_e
• ElectronMass: electron mass, m_e
• ElementaryCharge: elementary charge, e
• Faraday: Faraday constant, F
• FermiCoupling: Fermi coupling constant, G_F/(ħc)³
• FineStructure: fine-structure constant, α
• FluxQuantum: magnetic flux quantum, Φ₀
• Gravitational: Newtonian constant of gravitation, G
• HartreeEnergy: Hartree energy, E_h
• LightSpeed: speed of light, c
• Loschmidt: Loschmidt's number, n₀
• NuclearMagneton: nuclear magneton, μ_N
• Planck: Planck constant, h
• ProtonMass: proton mass, m_p
• ReducedPlanck: reduced Planck constant, ħ
• Rydberg: Rydberg constant, R_∞
• StefanBoltzmann: Steffan-Boltzmann constant, σ
• VacuumImpedeance: vacuum impedance, Z₀
• VacuumPermeability: vacuum permeability, μ₀
• VacuumPermittivity: vacuum permittivity, ε₀
• WienDisplacement: Wien displacement law constant, b