.. sld_calculator_help.rst .. This is a port of the original SasView html help file to ReSTructured text .. by S King, ISIS, during SasView CodeCamp-III in Feb 2015. SLD Calculator Tool =================== Description ----------- 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 .. ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ 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). TIPS! * 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). .. ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ .. note:: This help document was last changed by Steve King, 01May2015