# isotopic_abundance¶

plasmapy.atomic.isotopic_abundance(isotope: plasmapy.atomic.particle_class.Particle, mass_numb: Optional[numbers.Integral] = None) → numbers.Real

Return the isotopic abundances if known, and otherwise zero.

Parameters
• argument (str or int) – A string representing an element or isotope, or an integer representing the atomic number of an element.

• mass_numb (int, optional) – The mass number of an isotope, which is required if and only if the first argument can only be used.

Returns

iso_comp – The relative isotopic abundance in the terrestrial environment.

Return type

float

Raises
• InvalidIsotopeError – If the argument is a valid particle but not a valid isotope.

• InvalidParticleError – If the argument does not correspond to a valid particle or contradictory information is provided.

• TypeError – If the argument is not a str or int.

Notes

Isotopic composition data are most readily available for the terrestrial environment, so this function may not be wholly appropriate for space and astrophysical applications.

The data retrieved from this routine are those recommended by NIST as of 2017.

Examples

>>> isotopic_abundance('Pb-208')
0.524
>>> isotopic_abundance('hydrogen', 1)
0.999885