electric_charge

plasmapy.atomic.electric_charge(particle: plasmapy.atomic.particle_class.Particle) → astropy.units.quantity.Quantity

Return the electric charge (in coulombs) of a particle.

Parameters:

particle (str) – String representing an element or isotope followed by integer charge information.

Returns:

charge – The electric charge in coulombs.

Return type:

Quantity

Raises:
  • InvalidParticleError – If the argument does not correspond to a valid particle or contradictory information is provided.
  • ChargeError – If charge information for the particle is not available.
  • AtomicWarning – If the input represents an ion with an integer charge that is below -3.

Notes

This function supports two formats for integer charge information.

The first format is a string that has information for the element or isotope at the beginning, a space in between, and the integer charge information in the form of an integer followed by a plus or minus sign, or a plus or minus sign followed by an integer.

The second format is a string containing element information at the beginning, following by one or more plus or minus signs.

This function returns -1.6021766208e-19 C for electrons and 1.6021766208e-19 C for positrons.

Examples

>>> electric_charge('p+')
<<class 'astropy.constants.codata2014.EMCODATA2014'> name='Electron charge' value=1.6021766208e-19 uncertainty=9.8e-28 unit='C' reference='CODATA 2014'>
>>> electric_charge('H-')
<Quantity -1.60217662e-19 C>