Source code for

"""Isotope data extracted from NIST public website.

Source data has been compiled by NIST:

The atomic weights data were published in:

    J. Meija et al, Atomic weights of the elements 2013,
    Pure and Applied Chemistry 88, 265-291 (2016).

Isotopic compositions data were published in:

    Michael Berglund and Michael E. Wieser,
    Isotopic compositions of the elements 2009 (IUPAC Technical Report)
    Pure Appl. Chem., 2011, Vol. 83, No. 2, pp. 397-410

The relative atomic masses of the isotopes data were published in:

    M. Wang, G. Audi, A.H. Wapstra, F.G. Kondev, M. MacCormick, X. Xu,
    and B. Pfeiffer, The AME2012 Atomic Mass Evaluation,
    Chinese Phys. C 36 1603
from urllib import request

[docs]def download_isotope_data(): """Download isotope data from NIST public website. Relative atomic masses of individual isotopes their abundance (mole fraction) are compiled into a dictionary. Individual items can be indexed by the atomic number and mass number, e.g. titanium-48: >>> from import download_isotope_data >>> isotopes = download_isotope_data() >>> isotopes[22][48]['mass'] 47.94794198 >>> isotopes[22][48]['composition'] 0.7372 """ url = '' \ '?ele=&ascii=ascii&isotype=all' with request.urlopen(url) as fd: txt = raw_data = txt.decode().splitlines() return parse_isotope_data(raw_data)
def parse_isotope_data(raw_data): # In the list of raw data, a string containing only a series of underscores # preceeds the data for each element. So by getting the indexes of these # strings, we are recording where in the data each element starts indexes = [idx for (idx, line) in enumerate(raw_data) if "_____" in line] isotopes = {} for idx1, idx2 in zip(indexes, indexes[1:]): atomic_number = int(raw_data[idx1 + 1].split()[0]) isotopes[atomic_number] = dct = {} for isotope_idx in range(idx1 + 1, idx2): mass_number = int(raw_data[isotope_idx][8:12]) # drop uncertainty mass = float(raw_data[isotope_idx][13:31].split('(')[0]) try: composition = float(raw_data[isotope_idx][32:46].split('(')[0]) except ValueError: composition = 0.0 dct[mass_number] = {'mass': mass, 'composition': composition} return isotopes