Error message

[Sumit2506]

Sir,
 When I am calculating the Phonon Bandstructure of Carbon nano tube with near about 80 atoms,
I is always getting failed and showing the message some thing like "VNL has terminated in unusual way "
Please suggest me what should i do .....

With highest regard

[zh]

The job may be too heavy for your computer resource and it runs out of your memory.

If you use the primitive unit cell of periodic CNT, you can reduce the number of atoms in your simulations.

[Anders Blom]

See the tutorial, and try reducing the number of repetitions in the C direction.

[Horen]

See the tutorial, and try reducing the number of repetitions in the C direction.

I have the same problem,and Ialso see the tutorial,but I still do not know how to do.

[Sumit2506]

Sir,
I have reduced the repetition and run it with minimum no. of atoms possible, but it is again showing the same error message "The application has requested the run time to terminate it in unusual way .Please contact the application support team for more information", can You suggest me the minimum memory requirement for calculation of these properties with structure having the atoms near about 100.


With Highest Regard

[Anders Blom]

One should be aware that phonon calculations are heavy lifting. On the other hand, ok 100 atoms - but what method? With the Tersoff potential I can do a phonon spectrum calculation of a (5,5) CNT with a Stone-Wales defect (200 atoms in total) in under 2 minutes on my laptop. The calculation uses about 120 MB of memory.

But a phonon calculation with 100 atoms with DFT, it might need 2 or 8 or 16 GB or more, it's impossible to tell without knowing the details of the system.

[Sumit2506]

I am calculating the Phonon bandstructure of (5, 5) CNT with 4 repetition in Z direction ,Using my system which is having i7 processor and 2 GB ram

[Anders Blom]

2 GB is too little to do anything serious with DFT.