readme.lyx

已经编译好的levoo程序

\end_inset 


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This is menu-driven (similar to 
\series bold 
tetr
\series default 
).
 It is compiled only ones (in directory 
\family typewriter 
VASP_TOOLS
\family default 
) and used to work out the
\series bold 
 VASP
\series default 
 output and write down files which 
\series bold 
lev00 
\series default 
can understand.
 First, you run
\series bold 
 VASP 
\series default 
which produces
\family typewriter 
 OUTCAR
\family default 
 output file.
 Then, you run 
\series bold 
do_param
\series default 
 which does the following:
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first, read the output 
\family typewriter 
VASP
\family default 
 file
\layout Itemize

then, file 
\family typewriter 
param.inc
\family default 
 with all the parameters needed to compile 
\series bold 
lev00 
\series default 
should be written down.

\series bold 
 
\series default 
This is the 
\emph on 
main
\emph default 
 purpose of this utility.
\layout Itemize

file 
\family typewriter 
band.out
\family default 
 with eigenvalues can be also written; this is needed if DOS/LDOS will be
 analysed using 
\series bold 
lev00 
\series default 
and (this is important!) you had run 
\series bold 
tetr
\series default 
 before 
\series bold 
VASP
\series default 
 to create 
\family typewriter 
KPOINTS
\family default 
 and 
\family typewriter 
brill.dat
\layout Itemize

the output geometry file 
\family typewriter 
CONTCAR
\family default 
 of 
\series bold 
VASP
\series default 
 contains atomic coordinates in a way different from what you would expect;
 namely, 
\series bold 
VASP
\series default 
 adds lattice vectors to some atoms to have all their fractional coordinates
 between 0 and 1; this makes the subsequent analysis somewhat difficult.
 You can correct this problem if you have another geometry file with Cartesian/f
ractional coordinates of atoms at the positions associated with
\emph on 
 your 
\emph default 
choice of the zero cell.
 This, e.g., could be your initial geometry file you started the atomic relaxation
 from, so that there is a point to keep it.
 Make it e.g.
 
\family typewriter 
CONTCAR.ref
\family default 
 and allow 
\series bold 
do_param
\series default 
 to correct the problem in the 
\family typewriter 
CONTCAR
\family default 
 file produced after the 
\series bold 
VASP
\series default 
 run.
 The new file 
\family typewriter 
CONTCAR.new
\family default 
 will have atoms in the positions you expect them to be.
 This is an additional useful feature.
 Note that it is only needed to analyze the 
\series bold 
VASP
\series default 
 output and has nothing to do with 
\series bold 
lev00
\series default 
 package.
 You can also move 
\family typewriter 
CONTCAR.new
\family default 
 to 
\family typewriter 
CONTCAR
\family default 
.
 
\layout Itemize

Finally, the geometries in 
\family typewriter 
CONTCAR
\family default 
 and 
\family typewriter 
CONTCAR.ref
\family default 
 can be compared and file 
\family typewriter 
CONTCAR.
\family default 
dspl with displacements will be produced.
 This can also be proven to be useful! But do not forget first to correct
 positions of your atoms in 
\family typewriter 
CONTCAR
\family default 
 file (with respect e.g.
 to those in 
\family typewriter 
CONTCAR.ref
\family default 
 file) as otherwise the results will be wrong by some lattice vectors.
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Note that in the setting options at the bottom of the menu all the file
 names can be changed.
 The names used above are defaults.
\layout Subsection

What to do for the proper DOS/LDOS calculation ?
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First of all, if you want to get all the benefits of 
\series bold 
lev00 
\series default 
for the DOS option, run 
\series bold 
tetr
\series default 
 and create 
\begin_inset Formula \( \mathbf{k} \)
\end_inset 

-points in the file 
\family typewriter 
KPOINTS 
\family default 
and a look-up table of them in
\family typewriter 
 brill.dat
\family default 
.
 
\layout Enumerate

Then run 
\series bold 
VASP
\series default 
 with ICHARG=11 in 
\family typewriter 
INCAR
\family default 
 file to fix the electronic density (the band-structure option).
 
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After that you should run 
\series bold 
do_param
\series default 
 to get 
\family typewriter 
param.inc
\family default 
 and 
\family typewriter 
band.out
\family default 
 files from 
\family typewriter 
OUTCAR
\family default 
.
\layout Enumerate

Compile
\series bold 
 lev00 
\series default 
using the script 
\family typewriter 
lev00.comp
\family default 
 (provided).
 The file 
\family typewriter 
param.inc
\family default 
 will be used for that.
\layout Enumerate

Run 
\series bold 
lev00 
\series default 
as explained in the proper section below.
 
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In the case of the DOS calculation, you need only 
\family typewriter 
OUTCAR
\family default 
 file after 
\series bold 
VASP
\series default 
 run.
 In the case of the 
\begin_inset Formula \( s,p,d \)
\end_inset 

-projected DOS calculation, you will also need 
\family typewriter 
PROCAR
\family default 
 file.
 Note that RWIGS in the 
\family typewriter 
INCAR
\family default 
 file define the radii of the spheres for the calculation of the LDOS.
\layout Subsection

What to do for the electronic/spin/partial density ?
\layout Standard

For this calculation you can use the 
\begin_inset Formula \( \mathbf{k} \)
\end_inset 

-points of your ground state run.
 The sequence is, therefore, as follows:
\layout Enumerate

Run 
\series bold 
VASP
\series default 
 first.
 Total/spin densities are produced (the file
\family typewriter 
 CHGCAR
\family default 
) provided LCHARG flag in the 
\family typewriter 
INCAR
\family default 
 file is set to TRUE.
 To produce the partial charge density (the file 
\family typewriter 
PARCHG
\family default 
) - see the
\series bold 
 VASP
\series default 
 manual.
\layout Enumerate

After that you should run 
\series bold 
do_param
\series default 
 to get 
\family typewriter 
param.inc
\family default 
 file from 
\family typewriter 
OUTCAR
\family default 
.
\layout Enumerate

Compile
\series bold 
 lev00 
\series default 
using the script 
\family typewriter 
lev00.comp
\family default 
 (provided).
\layout Enumerate

Run 
\series bold 
lev00 
\series default 
as explained in the proper section below.
\layout Standard

You will need the following 
\series bold 
VASP 
\series default 
output files: 
\family typewriter 
CHGCAR 
\family default 
for the total density or total spin density calculation, or 
\family typewriter 
PARCHG
\family default 
 for the partial charge density.
\layout Section

Working with CASTEP
\layout Subsection

CASTEP 
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The 
\series bold 
CASTEP
\series default 
 code used in this package is basically the standard one.
 Only several modifications are necessary: 
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Wavefunctions (in reciprocal representation) are to be stored on a disk
 at the end of the band-structure run as a sequence of files 
\family typewriter 
fort.20
\family default 
, 
\family typewriter 
fort.21
\family default 
, 
\family typewriter 
fort.22
\family default 
, etc; one file per each 
\series bold 
k
\series default 
-point in the same order as they are given in the 
\family typewriter 
fort.15
\family default 
 file.
\layout Itemize

All eigenvalues ordered properly in ascending order should be delivered
 after the band-structure run to the file 
\family typewriter 
band.out 
\family default 
which has the following format: [k-point number, five eigenvalues] on every
 line.
 Note that this is compulsory as the utility 
\series bold 
take 
\series default 
(see below) does it anyway.
 It is important to have, however, properly ordered eigenvalues on the last
 
\series bold 
CASTEP
\series default 
 iteration.
\layout Itemize

The electronic density should be in 
\family typewriter 
fort.16
\family default 
 file.
\layout Standard

To compile the code you must prepare a standard file 
\family typewriter 
param.inc
\family default 
 in your
\emph on 
 
\shape italic 
working
\shape default 
\emph default 
 directory and then submit a shell-script 
\series bold 
comp
\series default 
 (supplied).
 After the compilation is completed, you will find in your working directory
 two executables: 
\series bold 
castepx
\series default 
 which is the 
\series bold 
CASTEP
\series default 
 itself and 
\series bold 
check
\series default 
 which is a check utility described below.
 
\layout Subsection

Utility 
\shape italic 
check
\layout Standard

This utility simulates a run of 
\series bold 
CASTEP
\series default 
: it reads all the data including pseudopotentials, density, etc., generates
 plane waves, etc.
 and then stops when all the preliminary work is done.
 If it reveals that some parameters set in the 
\family typewriter 
param.inc
\family default 
 file are insufficient, it will give a FATAL message with an advice about
 the least values for them.
 At the same time it gives error messages if it cannot open a file or cannot
 read it successfully.
 To compile the utility, submit the shell-script 
\series bold 
check.comp
\series default 
 from your current directory
\layout Subsection

Utility 
\shape italic 
take
\layout Standard

This utility 
\shape italic 
\emph on 
is used to assess the convergence of the band-structure run of 
\series bold 
CASTEP
\series default 
 and 
\shape default 
\emph default 
is compiled from your current working directory using a shell-script 
\series bold 
take.comp
\series default 
.
 Then, you can either run it with the name of the 
\series bold 
CASTEP
\series default 
 output in the command line or without it in which case you will be asked
 to specify this name explicitly:
\layout Standard


\latex latex 

\backslash 
begin{verbatim}
\newline 
 take   [name of the CASTEP output file]
\newline 

\backslash 
end{verbatim}
\latex default 
 
\layout Standard

The utility gives the following information about each 
\series bold 
CASTEP
\series default 
 band-structure iteration: 
\layout Itemize

actual iteration number 
\shape italic 
in the file
\shape default 
 and the 
\series bold 
CASTEP
\series default 
 iteration number; the former number differs from the latter if you keep
 not all the output in your output file (e.g., only several last iterations);
\layout Itemize

then, for each 
\series bold 

\begin_inset Formula \( \mathbf{k} \)
\end_inset 


\series default 
-point (
\family typewriter 
NKP
\family default 
) per line it gives 
\begin_inset Formula 
\begin{equation}
\label{9}
delta=\frac{1}{{\texttt {NBANDS}}}\sum _{n=1}^{{\texttt {NBANDS}}}\left| \epsilon _{n\mathbf{k}}^{{\texttt {NKP}}}-\epsilon _{n\mathbf{k}}^{{\texttt {NKP-1}}}\right| 
\end{equation}

\end_inset 

 which shows the convergence of the eigenvalues 
\begin_inset Formula \( \epsilon _{n\mathbf{k}}^{{\texttt {NKP}}} \)
\end_inset 

 on the current (
\family typewriter 
NKP
\family default 
-th) iteration with respect to the previous one ((
\family typewriter 
NKP-1
\family default 
)-th); it also compares the criteria with the previous iteration and checks
 if all the eigenvalues are properly ordered.
 If they are not ordered properly, it tells you how many weird eigenvalues
 have been met.
 (Note that if 
\series bold 
CASTEP
\series default 
 does the subspace rotation, this information is redundant.) 
\layout Standard

Usually, 
\begin_inset Formula \( delta=10^{-3} \)
\end_inset 

 is fine.
\layout Standard

At the end of the output you are asked to produce a file 
\family typewriter 
band.0
\family default