Extensible periodic table of the elements
Project description
This package provides a periodic table of the elements with support for mass, density and xray/neutron scattering information.
Masses, densities and natural abundances come from the NIST Physics Laboratory, but do not represent a critical evaluation by NIST scientists.
Neutron scattering calculations use values collected by the Atomic Institute of the Austrian Universities. These values do corresponding to those from other packages, though there are some differences depending to the tables used. Bound coherent neutron scattering for gold in particular is significantly different from older value: 7.63(6) as measured in 1974 compared to 7.90(7) as measured in 1990.
X-ray scattering calculations use a combination of empirical and theoretical values from the LBL Center for X-ray Optics. These values differ from those given in other sources such as the International Tables for Crystallography, Volume C, and so may give different results from other packages.
Change history
1.3.5 2013-02-26
New:
formulas now report charge and mass_fraction
formula parser accepts ions as Yy{#+} or Yy[#]{#+} for isotopes
support neutron activation calculations
support xray refraction index and mirror reflectivity
Modified:
update X-ray scattering tables for Zr
adjust ion mass for number of electrons
ions now display as Yy{#+} rather than Yy^{#+}
fix formula.natural_density
fix formula.hill so C,H come first
fix element.interatomic_distance
formula(value=…) -> formula(compound=…)
1.3 2010-12-05
New:
mix_by_weight and mix_by_volume formula constructors
use natural density to set density for isotope specific formulas
add neutron_scattering function which returns xs, sld and penetration depth
Modified:
need wavelength= or energy= for xray/neutron sld
improved docs and testing
1.2 2010-04-28
New:
support pickle: id(H) == id(loads(dumps(H)))
support ions, with magnetic form factors and x-ray f0 scattering factor
support py2exe wrappers
allow density to be calculated from structure (bcc, fcc, hcp, cubic, diamond)
estimate molecular volume
support private tables with some values replaced by application
Modified:
rename package periodictable
rename table to periodictable.elements
neutron sld returns real and imaginary coherent and incoherent instead of coherent, absorption and incoherent
bug fix: sld for H[2] was wrong when queried before sld for H.
remove CrysFML ionic radius definitions
1.1 2009-01-20
Modified:
Restructure package, separating tests into different directory
When defining table extensions, you should now do:
from elements.core import periodic_table, Element, Isotope
rather than:
from elements import periodic_table from elements.elements import Element, Isotope
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