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# Differences

This shows you the differences between two versions of the page.

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+ | **[//neutron_data//]** | ||

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+ | Signals the use of neutron atomic scattering lengths.Scattering lengths for isotopes can be used by placing the isotope name after “//occ//” as in: | ||

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+ | occ 6Li 1 | ||

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+ | occ 36Ar 1 | ||

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+ | The scattering lengths data, contained in the file NEUTSCAT.CPP, is from | ||

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+ | www.ccp14.ac.uk/ccp/web-mirrors/neutrons/n-scatter/n-lengths/LIST~1.HTM | ||

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+ | Constant wavelength neutron diffraction requires a Lorentz correction using the Lorentz_Factor macro (defined in TOPAS.INC); it is defined as follows: | ||

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+ | scale_pks = 1 / (Sin(Th)^2 Cos(Th)); | ||

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+ | **[//no_LIMIT_warnings//]** | ||

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+ | Surpresses [[#k157|LIMIT_MIN]] and LIMIT_MAX warning messages. | ||

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+ | **[//normalize_FCs//]** | ||

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+ | If defined then site fractional coordinates are normalized. Normalization of a particular fractional coordinate does not occur if it has //min/////max// limits, is part of a //rigid// body or part of a site constraint of any kind. | ||

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+ | **[//numerical_area// E]** | ||

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+ | Returns the numerically calculated area under the phase. |