Calculating energy of a structure

Alloy Theoretic Automated Toolkit (ATAT)
1

Dear Axel,

I have trouble with understanding how to get the energy of a structure by ATAT. Now I am just trying to learn how to use the program and get energy of a structure from built clusters and ECIs. I know a similar question was asked before but still I didn’t understand it clearly!

I am using the data you shared in ATAT tutorial (mcc_tialhcp1.tar (Pre-calculated files, pack 1)), and I run the command "maps -d &" and it generated many files including clusters.out and eci.out.

then I copied the same file of 5/str.out into a new place (lets say test/predictenr.out), then I run the command as you posted before "corrdump -c -s=test/predictenr.out -eci=eci.out" and it printed a value "-0.01401". and generated the corrdump.out file and maybe some more.
But my question is in energy file of structure 5, it is given as "-.24333739E+02". and when It predicts the energy of the same structure should it give the same/similar value or is there some unit difference?

in short how can I get/calculate the energy of a structure as like the input energy given for each structure?

I hope it is clear,
Thanks for your help,
Aman
PS: I also tried using new/different structure and it also gives some value but I think it is not exactly the energy of the strucuture.

2

There are two differences:

  1. corrdump gave you the energy per cell of the lattice (lat.in) while */energy is per cell of the structure (which is typically bigger).
  2. maps computes formation energies relative to the end members (pure elements, typically) before fitting the cluster expansion. You can turn that off by creating a ref_energy.in with zeros in it (2 zeros for a binary).
    Note that fit.out shows you the formation energies per cell of lat.in.
3

Thank you very much! this helps a lot!!!

Aman