Constants (`erlab.constants`)¶

Physical constants and unit conversion.

Module Attributes

`e`	Elementary charge \(e\) (C)
`c`	Speed of light \(c\) (m/s)
`m_e`	Electron mass \(m_e\) (kg) (±0.000 000 0028e-31)
`mcsq`	Electron rest energy \(m_e c^2\) (J) (±0.000 000 0025e-14)
`mcsq_eV`	Electron rest energy \(m_e c^2\) (eV) (±0.000 15)
`h`	Planck constant \(h\) (J·s)
`hc`	\(hc\) (J·m)
`hbar`	Dirac constant \(\hbar\) (J·s)
`hbarc`	\(\hbar c\) (J·m)
`hbarsq`	\(\hbar^2\) (J²·s²)
`h_eV`	Planck constant \(h\) (eV·s)
`hc_eV`	\(hc\) (eV·m)
`hbar_eV`	Dirac constant \(\hbar\) (eV·s)
`hbarsq_eV`	\(\hbar^2\) (eV²·s²)
`rel_eV_nm`	\(hc\) (eV·nm), Used in energy-wavelength conversion
`rel_kconv`	\(\frac{\sqrt{2 m_e}}{\hbar}\), Used in momentum conversion
`rel_kzconv`	\(\frac{\hbar^2}{2 m_e}\), Used in momentum conversion
`kb`	Boltzmann constant \(k_B\) (J/K)
`kb_eV`	Boltzmann constant \(k_B\) (eV/K)

Functions

`conv_eV_nm`(value)	Convert between energy and wavelength.
`conv_watt_photons`(value, wavelength)	Convert Watts to photons per second.

erlab.constants.TINY: float = 1e-15¶: From lmfit.lineshapes, equal to numpy.finfo(numpy.float64).resolution

erlab.constants.m_e: float = 9.1093837015e-31¶: Electron mass \(m_e\) (kg) (±0.000 000 0028e-31)

erlab.constants.m_n: float = 1.67492749804e-27¶: Neutron mass \(m_n\) (kg) (±0.000 000 000 95e-27)

erlab.constants.mcsq: float = 8.1871057769e-14¶: Electron rest energy \(m_e c^2\) (J) (±0.000 000 0025e-14)

erlab.constants.mcsq_eV: float = 510998.95¶: Electron rest energy \(m_e c^2\) (eV) (±0.000 15)

erlab.constants.hbar: float = 1.0545718176461565e-34¶: Dirac constant \(\hbar\) (J·s)

erlab.constants.hbarsq: float = 1.1121217185735183e-68¶: \(\hbar^2\) (J²·s²)

erlab.constants.h_eV: float = 4.135667696923859e-15¶: Planck constant \(h\) (eV·s)

erlab.constants.hbar_eV: float = 6.582119569509067e-16¶: Dirac constant \(\hbar\) (eV·s)

erlab.constants.hbarsq_eV: float = 4.332429802731423e-31¶: \(\hbar^2\) (eV²·s²)

erlab.constants.rel_eV_nm: float = 1239.8419843320028¶: \(hc\) (eV·nm), Used in energy-wavelength conversion

erlab.constants.a0: float = 5.29177210544e-11¶: Bohr radius \(a_0\) (m) (±0.000 000 000 82e-11)

erlab.constants.rel_kconv: float = 0.512316721967493¶: \(\frac{\sqrt{2 m_e}}{\hbar}\), Used in momentum conversion

erlab.constants.rel_kzconv: float = 3.8099821161548606¶: \(\frac{\hbar^2}{2 m_e}\), Used in momentum conversion

erlab.constants.kb_eV: float = 8.617333262145179e-05¶: Boltzmann constant \(k_B\) (eV/K)

erlab.constants.conv_eV_nm(value)[source]¶

Convert between energy and wavelength.

erlab.constants.conv_watt_photons(value, wavelength)[source]¶

Convert Watts to photons per second.

Parameters:

Returns:

power (float) – Power in photons per second.

Return type:

float

class erlab.constants.AxesConfiguration(*values)[source]¶

Enum class for different types of axes configurations in an ARPES experiment.

See Nomenclature and Ref. [Ishida and Shin, 2018] for more information.

Constants (erlab.constants)¶