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Extracting Hessian Matrix from OUTCAR file

Posted: Mon Sep 03, 2018 2:22 pm
by itando01
Hello
I performed a series of vibrational calculation in VASP using IBRION=5, and now i am looking for tools to extract the hessian matrix from the OUTCAR file i generated, in order to calculate thermodynamics properties. My question is two fold, are there script(s) for such task? and if so does one have to compile vasp code using vtst in order to use them?

Thanks

Re: Extracting Hessian Matrix from OUTCAR file

Posted: Mon Sep 03, 2018 6:56 pm
by graeme
With IBRION=5, vasp calculates the Hessian and the normal mode frequencies. Don't you just need the later for thermodynamic properties?

If you use the vtstcode, the dymmatrix.pl script generates the Hessian from forces printed in the OUTCAR file.

Re: Extracting Hessian Matrix from OUTCAR file

Posted: Tue Sep 04, 2018 6:00 pm
by itando01
Hello

Thanks a lot for your help, i haven't noticed that IBRION=5 writes out the eignvalues in OUTCAR, so all i need is there.