Author: Yuanpeng Zhang
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Magnetic Structure Refinement in RMCProfile
In RMCProfile, it is possible to refine the nucleus and magnetic structure altogether, and one can find detailed instructions in section 2.11 in the manual. The magnetic scattering will be calculated for both the Bragg diffraction and the total scattering pattern in reciprocal space (see the manual for detailed formulation). Specifically for the total scattering…
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Using Topas Bragg profile in RMCProfile
As a background note, we should talk a bit about why we add in the Bragg data in RMCProfile, which actually gives the program its current name — before the Bragg data is supported in RMCProfile, the program was called RMCA. In brief, the purpose is to constraint the model from the average structure perspective.…
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Using tail constraint in RMCProfile
Sometimes, the distance window constraint used in RMCProfile fitting will cause some spikes in the tail region of some partial PDFs. In this case, the tail constraint could be applied to suppress those unphysical spikes. To do this, one can refer to the following tutorial video, which uses OriginLab for extracting parameters of a Boltzmann…
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Data pre-processing for RMCProfile
General steps/checks to go through for a reasonable RMC fitting 1. Reciprocal space In RMCProfile, we follow the convention of defining symbols for various functions as presented in section-2 of Ref. [1]. It is always strongly recommended that before feeding the data into RMCProfile, we should check the format of the data to see whether it…
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How to launch RMCProfile program
In this post, detailed instructions will be presented concerning how to launch RMCProfile program on all platforms. Going through procedures covered in this post should guarantee a smooth start of RMCProfile program to enable the running of both the main rmcprofile program and those plotting routines. To enable the plot functionality, we need Xming server installed and…
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RMCProfile version 7 beta release
The beta version of RMCProfile 7 is now available to users on all platforms! Only main RMCProfile program is available with this release and no auxiliary programs were included. With version 7, one of the new major capabilities is mixed-phase fitting. However, it should be pointed out that with version 7, some key features with…
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Same type of atom on different sites in RMC fitting
Posted on November 11, 2021, by Yuanpeng Zhang In practice, there are many cases where we will have the same type of atom occupying different crystallographic sites, e.g., the A and B sites in spinel systems. Taking the high entropy spinel system as an example, if we want to treat atoms of the same type…
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Configure RMCProfile
Some tips for configuring RMCProfile on Unix/Linux system rmcprofile on cluster To run `rmcprofile` on cluster, the following bash script may be helpful, where WHEREVER_RMCProfile_FOLDER_IS_LOCATED refers to the main RMCProfile directory within which the exe and tutorial sub-directories are usually located. stem_name refers to whatever the stem name is for our RMC fitting. Put this script within RMC fitting directory and run…
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Calibration Issue Workaround
Solution to the commonly observed inconsistence between X-ray and neutron calibration Background Introduction The calibration issue is fundamentally concerned about the transformation in between d-spacing, wavelength and scattering angle, given the Bragg condition of scattering. Suppose we could possibly have hundred percent accurate measurement of those engineering values such as wavelength and scattering angle, we…