solprop.constants#
Physical constants in SI units.
Thin, named wrappers over scipy.constants (CODATA) so that the rest of the
package never spells a constant by hand. All values are SI (m, s, kg, J, W, V/m, Pa, K)
as fixed in docs/dev/conventions.md; the two non-SI pressure units are provided as
conversion factors because the user interface accepts pressures in bar.
Module Attributes
Speed of light in vacuum, m/s. |
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Vacuum permittivity, F/m. |
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Vacuum permeability, H/m. |
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Reduced Planck constant, J·s. |
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Planck constant, J·s. |
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Elementary charge, C. |
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Electron mass, kg. |
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Boltzmann constant, J/K. |
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Avogadro constant, 1/mol. |
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Fine-structure constant, dimensionless. |
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Bohr radius, m. |
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Atomic unit of energy (Hartree), J. |
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Atomic unit of electric field, V/m. |
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Atomic unit of electric polarisability, C^2 m^2 / J. |
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Atomic unit of time, s. |
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One bar in pascal. |
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One standard atmosphere in pascal. |
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Atomic mass constant (unified atomic mass unit), kg. |
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Loschmidt constant, m^-3. |
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The package-wide default temperature, K ( |
- solprop.constants.AMAGAT: float = 2.686780111798444e+25#
Loschmidt constant, m^-3.
The ideal-gas number density at 1 atm and 0 degrees Celsius.
The amagat is this quantity used as a unit; the Raman linewidth coefficients are tabulated in it. Exact in the SI since 2019, because the atmosphere, the Boltzmann constant and the temperature are all exact here.
- solprop.constants.ATOMIC_MASS: float = 1.66053906892e-27#
Atomic mass constant (unified atomic mass unit), kg.
- solprop.constants.AU_POLARISABILITY: float = 1.64877727212e-41#
Atomic unit of electric polarisability, C^2 m^2 / J.
The SI polarisability, not the volume polarisability: a static field
Eshifts a level by-alpha E^2 / 2, so the unit is an energy divided by a field squared. Equal toe^2 a_0^2 / E_h.
- solprop.constants.CHARGE_MASS_RATIO: float = 2.8179403208349128e-08#
e^2 / m_ein C^2/kg, the constant of the plasma’s free-electron current.The one derived constant here, rather than a CODATA value: the plasma response and the compiled plasma coefficients both need it, and the physics layer and the translation layer may not import each other.
- solprop.constants.ROOM_TEMPERATURE: float = 293.15#
The package-wide default temperature, K (
docs/dev/conventions.mdsection 1).20 °C, the usual laboratory reference and Luna’s room temperature (
roomtemp). Not a physical constant but a modelling default, kept here so that every module which needs one spells it the same way.