Reference Values

A number of reference values are avaliable through isopy.refval that are useful for geochemists.

All the reference values are readonly but dictionaries can be edited by creating a copy.

It is also possible to fetch reference values using asrefval() by passing a string with the name of the reference value as the first argument e.g. isopy.asrefval('isotope.mass').

refval.mass

isotopes

mass.isotopes

Dictionary containing all naturally occuring isotopes with a given mass number.

The dictionary is constructed from the isotopes in isotope.best_abundance_measurement_M16.

The get() method of this dictionary will return an empty IsotopeKeyList for absent keys.

Examples

>>> isopy.refval.mass.isotopes[40]
IsotopeKeyList('40Ar', '40K', '40Ca')

>>> isopy.refval.mass.isotopes.get(96)
IsotopeKeyList('96Zr', '96Mo', '96Ru')

refval.element

isotopes

element.isotopes

Dictionary containing all naturally occurring isotopes for each element symbol.

The dictionary is constructed from the isotopes in isotope.best_abundance_measurement_M16.

The get() method of this dictionary will return an empty IsotopeKeyList for absent keys.

Examples

>>> isopy.refval.element.isotopes['pd']
IsotopeKeyList('102Pd', '104Pd', '105Pd', '106Pd', '108Pd', '110Pd')

>>> isopy.refval.element.isotopes.get('ge')
IsotopeKeyList('70Ge', '72Ge', '73Ge', '74Ge', '76Ge')

all_symbols

element.all_symbols

A tuple of all the element symbols.

Examples

>>> isopy.refval.element.all_symbols[:5] # first 5 element symbols
(ElementKeyString('H'), ElementKeyString('He'), ElementKeyString('Li'),
 ElementKeyString('Be'), ElementKeyString('B'))

symbol_name

element.symbol_name

Dictionary containing the full element name mapped to the element symbol.

The first letter of the element name is capitalised.

The get() method of this dictionary will return None for absent keys.

Examples

>>> isopy.refval.element.symbol_name['pd']
'Palladium'

>>> isopy.refval.element.symbol_name.get('ge')
'Germanium'

name_symbol

element.name_symbol

Dictionary containing the element symbol mapped to the full element name.

The first letter of the element name must be capitalised.

The get() method of this dictionary will return None for absent keys.

Examples

>>> isopy.refval.element.symbol_name['Palladium']
ElementKeyString('Pd')

>>> isopy.refval.element.symbol_name.get('Germanium')
ElementKeyString('Ge')

atomic_number

element.atomic_number

Dictionary containing the atomic number for each element symbol.

The get() method of this dictionary will return None for absent keys.

Examples

>>> isopy.refval.element.atomic_number['pd']
46

>>> isopy.refval.element.atomic_number.get('ge')
32

atomic_weight

element.atomic_weight

Dictionary containing the atomic weight for each element symbol.

The atomic weights are calculated using the isotopic abundances from isotope.best_abundance_measurement_M16 and the isotopic masses from isotope.isotope.mass_W17.

The get() method of this dictionary will return None for absent keys.

Examples

>>> isopy.refval.element.atomic_weight['pd']
106.41532788648

>>> isopy.refval.element.atomic_weight.get('ge')
72.6295890304831

initial_solar_system_abundance_L09

element.initial_solar_system_abundance_L09

Dictionary containing the element abundance of the initial solar system composition (normalized to N(Si) = 10^6 atoms) from Lodders et al. (2019).

Reference: Lodders et al. (2019).

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

refval.element

isotopes

isotope.mass

Dictionary containing the default mass of each isotope.

This is the default dictionary used in functions where the isotope mass is required.

This dictionary is initially a copy of isotope.mass_W17 but can be changed by the user. Note the default values used can change in future versions of isopy as newer values become avaliable.

Examples

>>> isopy.refval.isotope.mass['pd105']
104.9050795

>>> isopy.refval.isotope.mass.get('ge76')
75.92140273

>>> isopy.refval.isotope.mass.get('pd108/pd105')
1.0285859589859039

fraction

isotope.fraction

Dictionary containing the default fraction of each isotope.

This is the default dictionary used in functions where the isotope abundance is required.

This dictionary is initially a copy of isotope.best_measurement_fracton_M16 but can be changed by the user. Note the default values used can change in future versions of isopy as newer values become avaliable.

Examples

>>> isopy.refval.isotope.best_measurement_fraction_M16['pd105']
0.2233

>>> isopy.refval.isotope.best_measurement_fraction_M16.get('ge76')
0.07745

>>> isopy.refval.isotope.best_measurement_fraction_M16.get('pd108/pd105')
1.1849529780564263

mass_number

isotope.mass_number

Dictionary containing mass number of each isotope.

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

Examples

>>> isopy.refval.isotope.mass_number['pd105']
105

>>> isopy.refval.isotope.mass_number.get('ge76')
76

>>> isopy.refval.isotope.mass_number.get('pd108/pd105')
1.0285714285714285

mass_W17

isotope.mass_W17

Dictionary containing isotope mass of each isotope from Wang et al. (2016).

Reference: Wang et al. (2016).

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

Examples

>>> isopy.refval.isotope.mass_W17['pd105']
104.9050795

>>> isopy.refval.isotope.mass_W17.get('ge76')
75.92140273

>>> isopy.refval.isotope.mass_W17.get('pd108/pd105')
1.0285859589859039

mass_AME20

isotope.mass_AME20

Dictionary containing isotope mass of each isotope from the 2020 Atomic Mass Evaluation.

Reference: Atomic Mass Evaluation 2020.

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

best_measurement_fraction_M16

isotope.best_measurement_fraction_M16

Dictionary containing the isotope fraction from the best avaliable measurement from Meija et al. (2016).

Reference: Meija et al. (2016).

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

Examples

>>> isopy.refval.isotope.best_measurement_fraction_M16['pd105']
0.2233

>>> isopy.refval.isotope.best_measurement_fraction_M16.get('ge76')
0.07745

>>> isopy.refval.isotope.best_measurement_fraction_M16.get('pd108/pd105')
1.1849529780564263

initial_solar_system_fraction_L09

isotope.initial_solar_system_fraction_L09

Dictionary containing the isotope fraction of the inital solar system composition from Lodders et al. (2019).

Reference: Lodders et al. (2019).

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

Examples

>>> isopy.refval.isotope.initial_solar_system_fraction_L09['pd105']
0.2233

>>> isopy.refval.isotope.initial_solar_system_fraction_L09.get('ge76')
0.0.07444

>>> isopy.refval.isotope.initial_solar_system_fraction_L09.get('pd108/pd105')
1.1849529780564263

initial_solar_system_abundance_L09

isotope.initial_solar_system_abundance_L09

Dictionary containing the isotope abundance of the inital solar system composition (normalized to N(Si) = 10^6 atoms) from Lodders et al. (2019).

Reference: Lodders et al. (2019).

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

Examples

>>> isopy.refval.isotope.initial_solar_system_abundance_L09['pd105']
0.3032

>>> isopy.refval.isotope.initial_solar_system_abundance_L09.get('ge76')
8.5

>>> isopy.refval.isotope.initial_solar_system_abundance_L09.get('pd108/pd105')
1.184036939313984

initial_solar_system_abundance_L09b

isotope.initial_solar_system_abundance_L09b

Dictionary containing the isotope abundance calcualted from the elemental abundance and the isotope fraction.

Note These values are not directly taken from the table but calculated from element.initial_solar_system_abundance_L09 and isotope.initial_solar_system_fraction_L09. This ensures consistency between all three reference values. Discrepancies between the calculated these isotope abundances and isotope.initial_solar_system_abundance_L09 are due to rounding errors.

Reference: Lodders et al. (2019).

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

Examples

>>> isopy.refval.isotope.initial_solar_system_abundance_L09['pd105']
0.303688

>>> isopy.refval.isotope.initial_solar_system_abundance_L09.get('ge76')
8.5606

>>> isopy.refval.isotope.initial_solar_system_abundance_L09.get('pd108/pd105')
1.1849529780564263

present_solar_system_fraction_AG89

isotope.present_solar_system_fraction_AG89

Dictionary containing the isotope fraction of the present solar system composition from Anders & Grevesse 1989.

Reference: Anders & Grevesse (1989).

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

initial_solar_system_abundance_AG89

isotope.initial_solar_system_abundance_AG89

Dictionary containing the isotope abundance of the initial solar system abundance from Anders & Grevesse 1989.

Data normalised such that normalized to N(Si) = 10^6 atoms.

Reference: Anders & Grevesse (1989).

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

present_solar_system_abundance_AG89

isotope.present_solar_system_abundance_AG89

Dictionary containing the isotope abundance of the present solar system abundance from Anders & Grevesse 1989.

Data normalised such that normalized to N(Si) = 10^6 atoms.

Reference: Anders & Grevesse (1989).

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

sprocess_fraction_B11

isotope.sprocess_fraction_B11

Dictionary containing the estimated s-process fraction of each isotope from Bisterzo et al. (2011).

Reference: Bisterzo et al. (2011).

The get() method of this dictionary will automatically calculate the ratio of two isotopes if both are present the dictionary. The get() method will return np.nan for absent keys.

Examples

>>> isopy.refval.isotope.initial_solar_system_abundance_L09['pd105']
0.157

>>> isopy.refval.isotope.initial_solar_system_abundance_L09.get('mo95')
0.696

>>> isopy.refval.isotope.initial_solar_system_abundance_L09.get('pd108/pd105')
4.751592356687898