19990805: summary about the influence of the starting configuration and the equilibration period on the oxygen diffusion coefficient

GOAL

Summary for the following calculations:

Results

How to get the following histograms

• The distances for each ionic pair can be obtained by running configdist on the LATTICE file generated by genlat. E.g. for the oxygen-oxygen distances:
  input_file   LATTICE
  max_shells   20
  max_centers  1   <<<otherwise one gets a huge file!!
  distance     O   O  0.1   10.0
  
• Once we have the list of distances, we run configdist on the CONFIG.VACA file. E.g., for the vacancy-vacancy pairs (called ``O1'' in CONFIG.VACA):
  input_file   CONFIG.VACA
  max_shells   20
  distance O1    O1   0.1   10.0
  
• At this point, edit the output of configdist from within emacs so as to leave a single column containing only the distances: the column will contain the same numbers found in the first step above, each repeated several times.
• To count how many times each distance occurs, use a shell script like this: #!/bin/sh
  for i in 3.77383172 5.33700400 6.53646828
          7.54766344 8.43854426 9.24396209 9.98462022
  do echo `egrep -c $i mom1`
  done
  where the numbers are the distances to be counted and mom1 is the file where the output of configdist was redirected
• IMPORTANT: for distances between identical pairs (e.g. $V_{O}^{\cdot\cdot}-V_{O}^{\cdot\cdot}$ or $Ce_{Zr}^{\prime}-Ce_{Zr}^{\prime}$) the output of the counting script must be divided by 2 (with calc, for instance)

Histogram of the $V_{O}^{\cdot\cdot}-V_{O}^{\cdot\cdot}$ distances for the various calculations:

Histogram of the $V_{O}^{\cdot\cdot}-Ce_{Zr}^{\prime}$ distances for the various calculations:

Histogram of the $Ce_{Zr}^{\prime}-Ce_{Zr}^{\prime}$ distances for the various calculations:

Comparison short vs long equilibration time:

Oxygen diffusion coefficients derived from the MSD plots:

Same table as above, but the comparison between short and long time equilibrated calculations is evidenced.