QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: chethankumar_m on November 21, 2016, 11:14

Title: total energy for hetro structure
Post by: chethankumar_m on November 21, 2016, 11:14

hi,
I am calculating the total energy of graphene-MoS2 heterostructure, total energy it is showing -2975.95839 eV is this value correct? how can we tell its in global minima and is there a way to calculate to find the multiple values of distance vs total energy in a single calculation.
Thank you

Title: Re: total energy for hetro structure
Post by: ams_nanolab on November 21, 2016, 21:31

Total energy / atom is a more realistic estimate maybe. To find global minima vary interlayer distance and calculate total energy/atom for each case, then just plot. You have to run an optimization loop for that purpose.   

Title: Re: total energy for hetro structure
Post by: Daniele Stradi on November 23, 2016, 08:50

In DFT the absolute value of the total energy does not have physical meaning, only differences between total energies have physical meaning.

It is possible to do the E vs. d curve in a single run by editing the script in a python code, but I strongly suggest you to avoid it if you don't know what you are doing. It is safer to do it in separate calculations.