Zero-point energies


#1

I have a need to calculate zero-point energies, but it does not appear that the phonon frequencies are available from the Materials Project calculations. Can they be made available?


#2

Dear @LesG

Currently, materials project does not compute phonon frequencies. Since it requires creation of larger supercell (if done through the finite difference method) or through DFPT which is very expensive, such calculations are not done in materials project.

However, pymatgen can be used to perform the phonon calculations using tools like phonopy (Refer to mapidoc for further information). But these calculations need to be done in a local machine and not on the computational resources at materials project.

“Can they be made available?”
–> Not possible at present. Maybe future versions might have this features.


#3

Hi @George_Yumnam,

I’m currently trying to find a way to compute phonon frequencies as well taking into account the whole Brillouin zone. Your answer to LesG’s question sounds interesting to me, but what exactly do you mean with “pymatgen can be used to perform the phonon calculations using tools like phonopy”?

I’ve taken a look at mapidoc, but it wasn’t that helpful to me. As far as I’ve have seen so far, pymatgen has an io.phonopy module which allows to process the output of phonopy computation. In that case the computation is done by phonopy and pymatgen is just used as a processing tool. Or do you mean that there is a way to use pymatgen for phonon frequency computation?

Thank you for your help in advance!


#4

Hi @quanhtum,

You are exactly right. The pymatgen module for phonopy only performs I/O operations.

However, for actually calculating the forces for each displaced cases (if using finite difference method, or similarly for DFPT), you need to prepare the input files and submit them: either using the vasp.io methods (Pymatgen VASP input), while submitting through MPRester SNL submission, or on your local machine.

Hope this helps.


#5

Hi @George_Yumnam,

thank you for your answer!