关注：

1）宝山岂能空回？如何

2）结构相变的分析

问：

Dear Andreas,      

    First of all, I hope everything goes very well with you.       Recently, I got some comments on my draft about scandium hydrides from Roald ,     " Do you have phonons of the two structures at two pressures -- say 1 atm and 100GPa? At two pressures, can you  Take the two structures, and run a linear transit between them, i.e interpolating distances  in a series of single-point calculations."    

    Could you kindly tell me  how to run a linear transit between the two structures? You can find the cif files of the NaCl-type ScH and the Cmcm ScH in the attachment.      Welcome to visit our academy some day.       Best wishes to you and your family!                         Sincerely yours,

                                             Xiaoqiu

Comments from Roald,

"the Cmcm structure looks to me like a distorted rock salt structure. If so, this needs to be said you need to say that. Moreover  its enthalpy is so close to rocksalt structure (old fig4, diamond and dotted lines)which makes me think there is a flat surface between the two structures.

Do you have phonons of the two structures at two pressures -- say 1 atm and 100GPa? At two pressures, can you  Take the two structures, and run a linear transit between them, i.e interpolating distances  in a series of single-point calculations.

答：

Dear Xiaoqiu,

附： make-interpolation.bash

#!/bin/bash

# Number of interpolated images
NINTERP=24

# Number of atoms in unit cell
NATOMS=4
# First frame:
POS1=CONTCAR-I41amd.vasp
# Final frame:
POS2=CONTCAR-C2m.vasp

# Pattern for interpolated file names (will be $POSINT$image.vasp):
POSINT=CONTCAR-step

A0X=`sed -n "3p" $POS1 | awk '{print $1}'`
A0Y=`sed -n "3p" $POS1 | awk '{print $2}'`
A0Z=`sed -n "3p" $POS1 | awk '{print $3}'`
B0X=`sed -n "4p" $POS1 | awk '{print $1}'`
B0Y=`sed -n "4p" $POS1 | awk '{print $2}'`
B0Z=`sed -n "4p" $POS1 | awk '{print $3}'`
C0X=`sed -n "5p" $POS1 | awk '{print $1}'`
C0Y=`sed -n "5p" $POS1 | awk '{print $2}'`
C0Z=`sed -n "5p" $POS1 | awk '{print $3}'`

for im in $(jot $((NINTERP+1)) 0 $NINTERP); do

sed -n "1,2p" $POS2 > $POSINT$im.vasp
sed -n "3p" $POS2 | awk -v ax=$A0X -v ay=$A0Y -v az=$A0Z -v im=$im -v nim=$NINTERP '{print ($1*im+ax*(nim-im))/nim,($2*im+ay*(nim-im))/nim,($3*im+az*(nim-im))/nim}' >> $POSINT$im.vasp
sed -n "4p" $POS2 | awk -v ax=$B0X -v ay=$B0Y -v az=$B0Z -v im=$im -v nim=$NINTERP '{print ($1*im+ax*(nim-im))/nim,($2*im+ay*(nim-im))/nim,($3*im+az*(nim-im))/nim}' >> $POSINT$im.vasp
sed -n "5p" $POS2 | awk -v ax=$C0X -v ay=$C0Y -v az=$C0Z -v im=$im -v nim=$NINTERP '{print ($1*im+ax*(nim-im))/nim,($2*im+ay*(nim-im))/nim,($3*im+az*(nim-im))/nim}' >> $POSINT$im.vasp
sed -n "6,7p" $POS2 >> $POSINT$im.vasp
#echo "Selective Dynamics" >> $POSINT$im.vasp
echo "Direct" >> $POSINT$im.vasp

done

for at in $(jot $NATOMS 9 $(( NATOMS + 8 )) ); do

AT0X=`sed -n "$at p" $POS1 | awk '{print $1}'`
AT0Y=`sed -n "$at p" $POS1 | awk '{print $2}'`
AT0Z=`sed -n "$at p" $POS1 | awk '{print $3}'`

for im in $(jot $NINTERP 1 $NINTERP); do

#sed -n "$at p" $POS2 | awk -v ax=$AT0X -v ay=$AT0Y -v az=$AT0Z -v im=$im -v nim=$NINTERP '{print ($1*im+ax*(nim-im))/nim,($2*im+ay*(nim-im))/nim,($3*im+az*(nim-im))/nim, " F F F"}' >> $POSINT$im.vasp
sed -n "$at p" $POS2 | awk -v ax=$AT0X -v ay=$AT0Y -v az=$AT0Z -v im=$im -v nim=$NINTERP '{print ($1*im+ax*(nim-im))/nim,($2*im+ay*(nim-im))/nim,($3*im+az*(nim-im))/nim}' >> $POSINT$im.vasp

done
done