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SLD Calculator Tool


The neutron scattering length density (SLD) is defined as

SLD = (b_c1 + b_c2 + ... + b_cn) / Vm

where b_ci is the bound coherent scattering length of ith of n atoms in a molecule with the molecular volume Vm

Specifying the Compound Name

To calculate scattering length densities enter the empirical formula of a compound and its mass density and click "Calculate".

Entering a wavelength value is optional (a default value of 6.0 |Ang| will be used).


  • Formula strings consist of atoms and the number of them, such as "CaCO3+6H2O".
  • Groups can be separated by '+' or space, so "CaCO3 6H2O" works as well.
  • Groups can be defined using parentheses, such as "CaCO3(H2O)6".
  • Parentheses can be nested, such as "(CaCO3(H2O)6)1".
  • Isotopes are represented by their atomic number in square brackets, such as "CaCO[18]3+6H2O", H[1], or H[2].
  • Numbers of atoms can be integer or decimal, such as "CaCO3+(3HO0.5)2".
  • The SLD of mixtures can be calculated as well. For example, for a 70-30 mixture of H2O/D2O write "H14O7+D6O3" or more simply "H7D3O5" (i.e. this says 7 hydrogens, 3 deuteriums, and 5 oxygens) and enter a mass density calculated on the percentages of H2O and D2O.
  • Type "C[13]6 H[2]12 O[18]6" for C(13)6H(2)12O(18)6 (6 Carbon-13 atoms, 12 deuterium atoms, and 6 Oxygen-18 atoms).


This help document was last changed by Steve King, 01May2015

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