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2000-03-07: using $\rho =0.25$ instead of $\rho =0.35$ in the $\xy+{H2};p+/r3em/+{O1}**\dir {-}\endxy$ Buckingham potential

GOAL

We try a different value of the $\rho$ parameter in the $\xy*+{H2};p+/r3em/*+{O1}**\dir {-}\endxy$ Buckingham potential, to see if this has any effect on the trend of the water incorporation energies.

Results

As in 2000-02-23, the starting orientation of the group was along the crystallographic direction.

$\begin{center} \begin{threeparttable} \begin{tabular}{lD{.}{.}{6}D{.}{.}{6}D{.}{... ...7250 & 718 & 6.19272785 & 1.07 \\ \end{tabular}\end{threeparttable}\end{center}$

Taking the $E_{V_O^{+1.9}}$ values from 2000-02-02 and the $E_{O_O^{-0.1}}$ from 2000-03-03, we have:

$\begin{center} \begin{threeparttable} \begin{tabular}{lD{.}{.}{8}D{.}{.}{8}D{.}{... ...140 & -1.74034295 & 1.43816725 \\ \end{tabular}\end{threeparttable}\end{center}$

The following figure compares 2000-03-03 with current calculation. The only difference is the $\rho$ value for the $\xy*+{H2};p+/r3em/*+{O1}**\dir {-}\endxy$ interaction.

$\begin{center}\vbox{\input{2000-03-07-01.pslatex} }\end{center}$

Final geometry

As said above, the starting orientation was along the [110] direction. The following table shows the angle $\theta$ beteween the $\xy* {O};p+/r2em/*{H}**\dir{-}?>*\dir{>}\endxy$ vector and the crystallographic direction and the $\xy*{O};p+/r2em/*{H}**\dir{-}\endxy$ bond distance in the relaxed configuration.

$\begin{threeparttable} \begin{tabular}{lllll} \multicolumn{1}{c}{Oxide} &\multic... ...2348,1.442374 & 2.009804,2.009804,2.009640 \\ \end{tabular}\end{threeparttable}$

$\begin{threeparttable} \begin{tabular}{lll} \multicolumn{1}{c}{Oxide} &\multicol... ...b_{0.2}O_{1.9}$} & 0.00904511 & 0.98275294 \\ \end{tabular}\end{threeparttable}$

Representative input file


opti conp defect regi_before nodsymmetry
#conp defect single
dump every 1 y-OH.dump
maxcyc  200
cutb 3.0 # what does this mean? Ronny uses it.
title
Yttrium solid solution
N.Sakai et al. Solid State Ionics 125(1999)325-331
end
cell
   5.430000 5.430000 5.430000  90.000000  90.000000  90.000000

size        9.77028241         20.00
centre      0.25   0.25   0.25
impurity     O2 core   0.25   0.25   0.25
interstitial H2 core   0.37354608 0.37354608 0.25000000
fractional   
############
# Cores
############
Ce4  core  0.000000   0.000000   0.000000  -3.700000 0.8
Y    core  0.000000   0.000000   0.000000   3.00     0.2
O1   core  0.250000   0.250000   0.250000   0.07700  0.95
############
# Shells
############
Ce4  shel  0.000000   0.000000   0.000000   7.700000 0.8
O1   shel  0.250000   0.250000   0.250000  -2.07700  0.95
space
225

#########################
# Shell-core charges
#########################
species   
Ce3   shel    7.700000
Ce3   core   -4.700000   
O2    core   -1.4263
H2    core    0.4263         
#########################
# Short range potentials
#########################
buck 
Ce4 shel O1 shel    1986.830000 0.351070   20.40000  0.0 15.000
Ce3 shel O1 shel    1731.61808  0.36372    14.43256  0.0 15.000
Y   core O1 shel    1345.1      0.34910     0.00000  0.0 15.000
O1  shel O1 shel   22764.300000 0.149000   27.89000  0.0 15.000
O2  core O1 shel   22764.300000 0.149000   27.89000  0.0 15.000
H2  core O1 shel     311.970    0.25        0.0      0.0 15.000
Ce4 shel O2 core    1986.830000 0.351070   20.40000  0.0 15.000
Y   core O2 core    1345.1      0.34910     0.00000  0.0 15.000
morse
H2  core O2 core       7.05250  2.19860     0.9485   1.0 0.0 2.0
#########################
# Spring parameters
#########################
spring 
Ce4    291.750000
Ce3    291.750000
O1      27.29