64 lines
3.4 KiB
Markdown
64 lines
3.4 KiB
Markdown
# PhysConst
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A collection of fundamental physical constants in various unit systems for MATLAB.
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## Licensing
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This software is licensed under the GNU General Public License (version 3).
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## Tested On
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- MATLAB R2013b - R2018a
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## Syntax
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`v=Constant.NameOfConstant` returns the value of the named constant in the default unit system. See the [list of physical constant names](https://github.com/heriantolim/PhysConst#list-of-physical-constant-names). For examples:
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- `v=Constant.ElementaryCharge` returns the value of the elementary charge, *e*;
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- `v=Constant.LightSpeed` returns the value of the speed of light, *c*.
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### Default Unit System
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By default, the values are returned in the [SI](https://en.wikipedia.org/wiki/International_System_of_Units) units. To set a different unit system as default, do one of the following:
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- Make a variable assignment: `UnitSystem='UnitSystemCode';`, where `UnitSystemCode` refers to the unit system to be used. See the [list of unit system codes](https://github.com/heriantolim/PhysConst#list-of-unit-system-codes).
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- Define an anonymous function: `UnitSystem=@()'UnitSystemCode';`.
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- 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.
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`v=Constant.UnitSystemCode.NameOfConstant` returns the value of the named constant in the specified unit system, regardless of the default unit system. For examples:
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- `v=Constant.SI.ElementaryCharge` returns the value of the elementary charge, *e*, in the SI units (=1.602176565);
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- `v=Constant.P.LightSpeed` returns the value of the speed of light, *c*, in the Planck units (=1).
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### Uncertainties
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`[v,u]=Constant.NameOfConstant` and `[v,u]=Constant.UnitSystemCode.NameOfConstant` additionally return the uncertainty of the named constant.
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## List of Unit System Codes
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- `HA`: Hartree Atomic Units
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- `P`: Planck Units
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- `QCD`: Quantum Chromodynamics Units
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- `RA`: Rydberg Atomic Units
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- `S`: Stoney Units
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- `SI`: International System of Units
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## List of Physical Constant Names
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- `AtomicMass`: atomic mass unit, *m*<sub>u</sub>
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- `AvogadroNumber`: Avogadro's number, *N*<sub>A</sub>
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- `BohrMagneton`: Bohr magneton, *μ*<sub>B</sub>
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- `BohrRadius`: Bohr radius, *a*<sub>0</sub>
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- `Boltzmann`: Boltzmann constant, *k*<sub>B</sub>
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- `ConductanceQuantum`: conductance quantum, *G*<sub>0</sub>
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- `Coulomb`: Coulomb constant, *k*<sub>e</sub>
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- `ElectronMass`: electron mass, *m*<sub>e</sub>
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- `ElementaryCharge`: elementary charge, *e*
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- `Faraday`: Faraday constant, *F*
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- `FermiCoupling`: Fermi coupling constant, *G*<sub>F</sub>/(*ħc*)<sup>3</sup>
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- `FineStructure`: fine-structure constant, *α*
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- `FluxQuantum`: magnetic flux quantum, Φ<sub>0</sub>
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- `Gravitational`: Newtonian constant of gravitation, *G*
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- `HartreeEnergy`: Hartree energy, *E*<sub>h</sub>
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- `LightSpeed`: speed of light, *c*
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- `Loschmidt`: Loschmidt's number, *n*<sub>0</sub>
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- `NuclearMagneton`: nuclear magneton, *μ*<sub>N</sub>
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- `Planck`: Planck constant, *h*
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- `ProtonMass`: proton mass, *m*<sub>p</sub>
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- `ReducedPlanck`: reduced Planck constant, *ħ*
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- `Rydberg`: Rydberg constant, *R*<sub>∞</sub>
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- `StefanBoltzmann`: Steffan-Boltzmann constant, *σ*
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- `VacuumImpedeance`: vacuum impedance, *Z*<sub>0</sub>
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- `VacuumPermeability`: vacuum permeability, *μ*<sub>0</sub>
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- `VacuumPermittivity`: vacuum permittivity, *ε*<sub>0</sub>
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- `WienDisplacement`: Wien displacement law constant, *b*
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