QuantumATK Forum

QuantumATK => General Questions and Answers => Topic started by: ams_nanolab on July 10, 2017, 07:49

Title: Energy per atom of metal
Post by: ams_nanolab on July 10, 2017, 07:49

How to calculate energy/atom of metals as Li or Na (bulk) ?

Title: Re: Energy per atom of metal
Post by: Petr Khomyakov on July 10, 2017, 08:54

You can calculate the total energy using the analysis object 'Total energy' and divide it by the number of atoms to get the total energy per atom.

Title: Re: Energy per atom of metal
Post by: ams_nanolab on July 10, 2017, 09:04

In the case of Na for example, I add the BCC Na structure from database (i.e. Na(beta)), use 16x16x16 k-points to simulate bulk and as the cell contains just one atom, that should be the total energy/atom (Em) of BCC Na?

Also how I get the cohesive energy of Na? Simulate a single na atom and subtract from previous energy/atom(Em)?

Title: Re: Energy per atom of metal
Post by: Petr Khomyakov on July 10, 2017, 11:51

Quote from: ams_nanolab on July 10, 2017, 09:04

In the case of Na for example, I add the BCC Na structure from database (i.e. Na(beta)), use 16x16x16 k-points to simulate bulk and as the cell contains just one atom, that should be the total energy/atom (Em) of BCC Na?

Yes. Otherwise, the total energy of an ideal crystal is infinite because it is comprised of an infinite number of atoms.

Quote from: ams_nanolab on July 10, 2017, 09:04

Also how I get the cohesive energy of Na? Simulate a single na atom and subtract from previous energy/atom(Em)?

I guess so, see https://en.wiktionary.org/wiki/cohesive_energy.