Full Potential (lmf) Core-Level Spectroscopy

Table of Contents

Preliminaries


This tutorial assumes you have cloned and built the lm repository (located here). For the purpose of demonstration, ~/lm will refer to the location of the cloned repository (source directory). In practice, this directory can be named differently.

All instances of commands assume the starting position is your build directory (this can be checked with the pwd command). In this tutorial it will be called ~/build/.

$ cd ~/build/

with ~/build being the directory the lm repository was built in to.

Note: the build directory should be different from the source directory.

Tutorial


Performing core level spectroscopy using the lmf code is exemplified in these test cases

$ fp/test/test.fp fe 2
$ fp/test/test.fp cr3si6 2
$ fp/test/test.fp crn with a core hole

Should you want a more in depth look, or a practical example, these are good places to start. We will use these as a base and go through the steps required to generate the partial DOS.

An input file is needed for the material of which the partial DOS should be found. A tutorial detailing the steps required to generate a basic input file can be found here. While this tutorial concerns itself with CrN, the steps involved are applicable to most other materials.

In this tutorial we will use the material Chromium Nitrate, CrN. Our input file, created previously, will be referred to as ctrl.crn and should be named as such.

We begin by running lmfa progam which needs to be run before any lmf process in order to generate the free-atom densities which, in our case, is generated in to the file atm.crn with the command

$ lmfa gas

We can now proceed with our lmf commands

$ lmf crn
$ lmf crn --rs=1,0 --cls:5,0,1 -vnit=1 -vmetal=2

Note that the lmf command is run twice - this is intended; the first run ensures a self-consistent solution. Particular attention should be paid to the –cls flag - the flag which tells lmf to perform core level spectroscopy on CrN. This will generate a variety of files needed to build to perform our core level spectroscopy.

We then run

$ lmdos --dos:cls:window=0,1:npts=101 --cls crn

Again, note the use of the –cls flag. This makes use of the previously generated files and generates the dos.crn file which contains our partial DOS information. This can be plotted with your preferred plotting tool, although some manipulation of the data in the file may be required.

A plotting tool is included in the suite, fplot, which can be used to generate a postscript file. We must first prepare the dos.crn file with another program in the suite, pldos, with the command

$ echo .25 10 0 1 | pldos -fplot -lst="1;3;5" -lst2="2;4;6" dos.crn

Which generates a plot.dos file readable by fplot. We follow this with an fplot command

$ fplot -disp -pr10 -f plot.dos

Which should result in a viewable image of the CLS DOS.


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