1.Ensure you compute your input file correctly, check your ibrav to confirm if
it correlate with that of orthorombic and tetragonal, check the required
celldm(1)..celldm(6) and make sure you used the correct cell dimension assigned
to your lattice structure through INPUT_PW.html
2. You should have an idea of the experimental lattice or optimized lattice
parameter from other research work you can find around, then set your celldm(1)
to + or - the optimized lattice parameter you got while other lattice
parameters become constante.g if the optimized celldm(1) from other research or
experimental value is 10 bohr you can vary your celldm(1) from 8 bohr to 12
bohr with an increment of 0.02, which depends on how much computation resource
or how expensive your computation is.
if you get a linear graph with positive gradient you next celldm trial should
be less than your minimum celldm from your graph but if your linear graph is
such that its gradient is negative you next trial for celldm should be higher
than your minimum celldm from your graph...
Good luck.
Agbaoye Ridwan OlamideFederal University of Agriculture, AbeokutaM.Sc. in view
On Thursday, January 21, 2016 12:49 AM, efi dwi indari
<[email protected]> wrote:
Dear All,
I am now on my way in determining stable lattice parameter of both orthorhombic
and tetragonal structures. Previously everything was going well when I
calculated the cubic one as I obtained the U-curve from which I got the value
of stable lattice parameter which corresponds to the lowest total energy.
Yet, when I move forward to the orthorhombic and tetragonal ones and when I
varied one of the lattice parameters (while the other(s) remains constant), I
could not obtain the U-curve. Instead, I got a linear curve, with lower total
energy as I go to smaller lattice parameter. Does anyone have any idea how to
deal with this issue? I have already googled but unfortunately not yet found
any solution.
Any help would be really appreciated. Thank you in advance.
Best Regards,
Efi Dwi Indari
Research assistant, Bandung Institute of Technology
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