# BaTiO3 forces wrong using PAW psp

**URL:** <https://discourse.abinit.org/t/batio3-forces-wrong-using-paw-psp/108>\
**Category:** Ground state\
**Created:** [April 30, 2021, 5:58pm UTC](https://discourse.abinit.org/t/batio3-forces-wrong-using-paw-psp/108 "2021-04-30T17:58:20Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![jiahaoz](https://discourse.abinit.org/letter_avatar_proxy/v4/letter/j/fbc32d/32.png) [@jiahaoz](https://discourse.abinit.org/u/jiahaoz)\
**Post date:** [April 30, 2021, 5:58pm UTC](https://discourse.abinit.org/t/batio3-forces-wrong-using-paw-psp/108/1 "2021-04-30T17:58:20Z")

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# Hello everyone, I was calculating the forces of BaTiO3 under the electrical field. However, I found that the force is not accurate. However, if I switch to Norm Conserving PSP. The results agree so well. I mean F=Q \times E. Any thing wrong with the PAW psp? I posted my input here:

nstep 50  
ecut 25  
ecutsm 0.5  
pawecutdg 35  
pawxcdev 0  
occopt 1  
prtwf 1  
prtden 0  
prteig 0  
toldfe 1.0d-12

ndtset 2  
jdtset 1 2  
berryopt1 -1 rfdir1 1 1 1  
berryopt2 4 efield2 0.000090692911356079 0.0000900338351967555 0.001058527828369657 getwfk2 1

acell 4.0811309814 4.0810610490 4.0809919294 angstrom  
rprim 1.0 0.0 0.0  
0.0 1.0 0.0  
0.0 0.0 1.0

#Structural parameters  
natom 5 # two atoms in the cell  
ntypat 3  
nband 20  
typat 1 2 3 3 3  
znucl 56 22 8  
xred 0.00188030 0.00189342 0.01764798  
0.51634006 0.51635532 0.52810615  
0.97257751 0.48515228 0.48726470  
0.48513157 0.97260416 0.48725646  
0.48455555 0.48457207 0.97577099

# Kpoint Grid

symmorphi 0  
kptopt 1  
ngkpt 6 6 6  
nshiftk 1 # this Monkhorst-Pack shift pattern is used so that the symmetry of the shifted grid

# is correct. A gamma-centered grid would also have the correct symmetry but would be

# less efficient.

shiftk 1.0 1.0 1.0

pp\_dirpath “$ABI\_PSPDIR”

# pseudos “pbe\_s\_sr/Ba.psp8,pbe\_s\_sr/Ti.psp8,pbe\_s\_sr/O.psp8”

# pseudos “pbe\_s\_sr/Ba.psp8,pbe\_s\_sr/Ti.psp8,pbe\_s\_sr/O.psp8”

pseudos “ATOMICDATA/Ba.GGA\_PBE-JTH.xml,ATOMICDATA/Ti.GGA\_PBE-JTH.xml,ATOMICDATA/O.GGA\_PBE-JTH.xml”

# pseudos “BTO/Ba.GGA\_PBE-JTH.xml,BTO/Ti.GGA\_PBE-JTH.xml,BTO/O.GGA\_PBE-JTH.xml”

# pseudos “BTO/Ba.xml,BTO/Ti.xml,BTO/O.xml”

# pseudos “BTO/Ba.xml.gz,BTO/Ti.xml.gz,BTO/O.xml.gz”

===================  
Best wishes  
Jiahao