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About the optimization of Nanotube
Posted: Wed Dec 20, 2006 2:51 am
by lanjh
In order to study the property of CNT, I need to optimize its structure. As we know, CNT just has periodic boundary condition in the axial direction. So I think I should use a lateral separation between tube centers to make sure that CNT do not interact with their periodic images. My work are doing with VASP.
Am I right? If I am right, how to set the seperation?
About the optimization of Nanotube
Posted: Wed Dec 20, 2006 12:36 pm
by tjf
[quote="]If I am right, how to set the seperation?[/quote"]
Assuming that you meen picking an appropriate distance, in general you need to run some calculations at different seperations to look at how far apart the nanotubes need to be to not change the energy (and/or the forces). I'd be willing to accept that different tubes would require different minimum seperations depending on whether they were metallic or not.
I'd guess that something like 10 Ang would be required. Others who have more experience with this type of system may like to comment.
About the optimization of Nanotube
Posted: Wed Oct 14, 2009 9:50 am
by sri123
hi..
the obsolute distance between the nanotubes will be varied with the size of the nanotubes. for larger CNT it will be increasing (say 40 Angstroms for [24 0] cnt). you have mention this seperation in the POSCAR file. for example
cnt240
1.0000
40.000000 0.0000000 0.0000000
0.0000000 40.000000 0.0000000
0.0000000 0.0000000 4.2300000
96
Direct
since nanotubes extend 1-dimensionally the above lattice parameters indicates that the CNT is extended in Z-direction and in X & Y it is separated by 40 Angstroms from other nanotubes.
hope it will help u