1 | .. sld_calculator_help.rst |
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2 | |
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3 | .. This is a port of the original SasView html help file to ReSTructured text |
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4 | .. by S King, ISIS, during SasView CodeCamp-III in Feb 2015. |
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5 | |
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6 | .. |Ang| unicode:: U+212B |
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7 | |
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8 | SLD Calculator Tool |
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9 | =================== |
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10 | |
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11 | Description |
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12 | ----------- |
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13 | |
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14 | The neutron scattering length density (SLD) is defined as |
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15 | |
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16 | SLD = (b_c1 + b_c2 + ... + b_cn) / Vm |
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17 | |
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18 | where b_ci is the bound coherent scattering length of ith of n atoms in a molecule |
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19 | with the molecular volume Vm |
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20 | |
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21 | .. ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ |
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22 | |
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23 | Specifying the Compound Name |
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24 | ---------------------------- |
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25 | |
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26 | To calculate scattering length densities enter the empirical formula of a |
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27 | compound and its mass density and click "Calculate". |
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28 | |
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29 | Entering a wavelength value is optional (a default value of 6.0 |Ang| will |
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30 | be used). |
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31 | |
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32 | TIPS! |
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33 | |
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34 | * Formula strings consist of atoms and the number of them, such as "CaCO3+6H2O". |
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35 | |
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36 | * Groups can be separated by *'+'* or *space*, so "CaCO3 6H2O" works as well. |
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37 | |
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38 | * Groups can be defined using parentheses, such as "CaCO3(H2O)6". |
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39 | |
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40 | * Parentheses can be nested, such as "(CaCO3(H2O)6)1". |
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41 | |
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42 | * Isotopes are represented by their atomic number in *square brackets*, such |
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43 | as "CaCO[18]3+6H2O", H[1], or H[2]. |
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44 | |
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45 | * Numbers of atoms can be integer or decimal, such as "CaCO3+(3HO0.5)2". |
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46 | |
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47 | * The SLD of mixtures can be calculated as well. For example, for a 70-30 |
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48 | mixture of H2O/D2O write "H14O7+D6O3" or more simply "H7D3O5" (i.e. this says |
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49 | 7 hydrogens, 3 deuteriums, and 5 oxygens) and enter a mass density calculated |
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50 | on the percentages of H2O and D2O. |
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51 | |
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52 | * Type "C[13]6 H[2]12 O[18]6" for C(13)6H(2)12O(18)6 (6 Carbon-13 atoms, 12 |
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53 | deuterium atoms, and 6 Oxygen-18 atoms). |
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54 | |
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55 | .. ZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZZ |
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56 | |
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57 | .. note:: This help document was last changed by Steve King, 01May2015 |
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58 | |
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