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error: increase the input variable dilatmx

Posted: Fri Oct 28, 2011 1:05 pm
by Paul
Hi,
When I test the ecut of the BaTiO3, it has a error:
The new primitive vectors rprimd (an evolving quantity)
are too large with respect to the old rprimd and the accompanying dilatmx :
this large change of unit cell parameters is not allowed by the present value of dilatmx.
You need at least dilatmx= 7.647588E+00


And this is my .in file:

ndtset 20
occopt 4
tsmear 0.05

acell 7.56 7.56 7.56
rprim 1 0 0
0 1 0
0 0 1

ntypat 3
znucl 56 22 8
natom 5
typat 1 2 3 3 3
xangst 0.000000000 0.000000000 0.000000000
1.999900000 1.999900000 2.009000000
1.999900000 1.999900000 0.000000000
1.999900000 0.000000000 2.009000000
0 2 2
ecut: 10 ecut+ 1
ixc -101130

optcell 1
ionmov 3
dilatmx 1.2
ntime 100
ecutsm 0.5

ngkpt 2 2 2
nshiftk 1
shiftk 0.5 0.5 0.5

nstep 100
toldfe 1.0d-6

Can someone tell me how to sole it ? And whether the variable rpirim which I set is worry.
Thanks~

Re: error: increase the input variable dilatmx

Posted: Fri Oct 28, 2011 3:27 pm
by blackburn
You have oxygen with norm-conversing psp (is that right?). You need a large cut-off (ecut) of the order of 50 Ha.

Simon