QuantumATK Forum
QuantumATK => General Questions and Answers => Topic started by: mldavidhuang on May 15, 2011, 06:59
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I was using ATK to calculate a system consisting of two layers of graphene nanoribbon with the interlayer distance is 8 Angstrom(the script of my model is attached) ,but as the calculation began there is error as follows, could anyone explain to me what is the problam?
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Calculating Eigenvalues :
** Back Engine Exception 541 : Diagonalization error, overlap matrix not positive definite, try to increase interaction_max_range
** Location : mathutils.cpp:1123
This application has requested the Runtime to terminate it in an unusual way.
Please contact the application's support team for more information.
NanoLanguageScript execution failure
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A similar problem has been discussed here:
http://quantumwise.com/forum/index.php?topic=853.0
I tested the configuration in your script file using the SZP basis set. It works well.
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But could you tell me how to increase the interaction_max_range ? I find no such parameter in the calculator settings
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It's under "Numerical Accuracy Parameters" for Huckel, but not relevant for DFT.
8 Å seems rather extreme, it means the two layers are not interacting, so you might as well just have one...
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But I want to compare the properties of bilayer GNR 's dependence for interlayer distance. you mean such interlayer distance is not reasonable for a two layer system? So it is meaningless, right?
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This distance is so large that you essentially have decoupled sheets. That's not meaningless, but don't go larger, just smaller. Reasonable interlayer distances lie in the range up to 5 Å, at you can easily find in the literature, e.g. APL 92, 223106 (2008) (http://dx.doi.org/10.1063/1.2938058) :)
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Thanks for your answer and reference!