hi all,
1.I would like to ask how to use vasp for simulating nano tubes? also
2.is there any provision where i can specify an hypothetical structure by specifying all the atomic positions and do ab inition calculations on the structure?
application to nano tubes
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saurabhroy
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application to nano tubes
Last edited by saurabhroy on Wed Dec 28, 2005 7:43 pm, edited 1 time in total.
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admin
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application to nano tubes
1) simply give the atoms' coordinates in your POSCAR file and
an choose an appropriate k-mesh (KPOINTS), concerning the periodicity of the cell
2) I am sorry, I fear maybe I do not understand that question correctly....
-- the atomic positions are given in POSCAR
-- the geometry can be optimized by specifying the following tags in INCAR :
IBRION choose the ionic relaxation algorithm
NSW fix the maximum number of ionic steps of a job
EDIFFG breaking condition, this specifies your convergence criterium:
>0 total energy convergence ,
ISIF calculate the stress tensor to relax the ionic positions, and/or cell shape, and/or cell volume. please mind that PREC has to be set to Accurate to provide reliable stress tensors)
all these tags are discussed in detail in the online handbook
http://cms.mpi.univie.ac.at/CMSPage/main
an choose an appropriate k-mesh (KPOINTS), concerning the periodicity of the cell
2) I am sorry, I fear maybe I do not understand that question correctly....
-- the atomic positions are given in POSCAR
-- the geometry can be optimized by specifying the following tags in INCAR :
IBRION choose the ionic relaxation algorithm
NSW fix the maximum number of ionic steps of a job
EDIFFG breaking condition, this specifies your convergence criterium:
>0 total energy convergence ,
ISIF calculate the stress tensor to relax the ionic positions, and/or cell shape, and/or cell volume. please mind that PREC has to be set to Accurate to provide reliable stress tensors)
all these tags are discussed in detail in the online handbook
http://cms.mpi.univie.ac.at/CMSPage/main
Last edited by admin on Tue Jan 10, 2006 8:50 am, edited 1 time in total.
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Damien
application to nano tubes
Hi saurabhroy,
You will find what you need by reading:
http://ej.iop.org/links/q83/UCUv86Jph+U ... _1_125.pdf
where they explain how to simulate nanotubes.
Damien
You will find what you need by reading:
http://ej.iop.org/links/q83/UCUv86Jph+U ... _1_125.pdf
where they explain how to simulate nanotubes.
Damien
Last edited by Damien on Tue Jan 24, 2006 9:27 am, edited 1 time in total.
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lmiao
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application to nano tubes
the link is not accessable. Can you copy again? thanks
Last edited by lmiao on Tue Jan 24, 2006 4:27 pm, edited 1 time in total.
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Damien
application to nano tubes
Hi,
You will find information in:
New Journal of Physics 5 (2003) 125.1–125.21 (http://www.njp.org/)
In fact, You are going to simulate like a tetragonal arrangement of nanotubes.
*
* * *
*
with a distance l between them. l needs to be large enough to avoid interaction.
So, your supercell is a cube and your basis set vectors are orthogonal.Your nanotube is placed around z-axis, so
norm(z)=length of your nanotube
norm(x)=norm(y)=diameter of nanotube + l
where (x,y,z is my basis set vectors)
I hope that my explication will help you
Damien
You will find information in:
New Journal of Physics 5 (2003) 125.1–125.21 (http://www.njp.org/)
In fact, You are going to simulate like a tetragonal arrangement of nanotubes.
*
* * *
*
with a distance l between them. l needs to be large enough to avoid interaction.
So, your supercell is a cube and your basis set vectors are orthogonal.Your nanotube is placed around z-axis, so
norm(z)=length of your nanotube
norm(x)=norm(y)=diameter of nanotube + l
where (x,y,z is my basis set vectors)
I hope that my explication will help you
Damien
Last edited by Damien on Wed Jan 25, 2006 1:22 pm, edited 1 time in total.