# Physical constants (rmgpy.constants)¶

The rmgpy.constants module contains module-level variables defining relevant physical constants relevant in chemistry applications. The recommended method of importing this module is

import rmgpy.constants as constants


so as to not place the constants in the importing module’s global namespace.

The constants defined in this module are listed in the table below:

Physical constants defined in the rmgpy.constants module
Symbol Constant Value Description
$$E_\mathrm{h}$$ E_h $$4.35974434 \times 10^{-18} \ \mathrm{J}$$ Hartree energy
$$F$$ F $$96485.3365 \ \mathrm{C/mol}$$ Faraday constant
$$G$$ G $$6.67384 \times 10^{-11} \ \mathrm{m^3/kg \cdot s^2}$$ Newtonian gravitational constant
$$N_\mathrm{A}$$ Na $$6.02214179 \times 10^{23} \ \mathrm{mol^{-1}}$$ Avogadro constant
$$R$$ R $$8.314472 \ \mathrm{J/mol \cdot K}$$ gas law constant
$$a_0$$ a0 $$5.2917721092 \times 10^{-11} \ \mathrm{m}$$ Bohr radius
$$c$$ c $$299792458 \ \mathrm{m/s}$$ speed of light in a vacuum
$$e$$ e $$1.602176565 \times 10^{-19} \ \mathrm{C}$$ elementary charge
$$g$$ g $$9.80665 \ \mathrm{m/s^2}$$ standard acceleration due to gravity
$$h$$ h $$6.62606896 \times 10^{-34} \ \mathrm{J \cdot s}$$ Planck constant
$$\hbar$$ hbar $$1.054571726 \times 10^{-34} \ \mathrm{J \cdot s}$$ reduced Planck constant
$$k_\mathrm{B}$$ kB $$1.3806504 \times 10^{-23} \ \mathrm{J/K}$$ Boltzmann constant
$$m_\mathrm{e}$$ m_e $$9.10938291 \times 10^{-31} \ \mathrm{kg}$$ electron rest mass
$$m_\mathrm{n}$$ m_n $$1.674927351 \times 10^{-27} \ \mathrm{kg}$$ neutron rest mass
$$m_\mathrm{p}$$ m_p $$1.672621777 \times 10^{-27} \ \mathrm{kg}$$ proton rest mass
$$m_\mathrm{u}$$ amu $$1.660538921 \times 10^{-27} \ \mathrm{kg}$$ atomic mass unit
$$\pi$$ pi $$3.14159 \ldots$$