[gpaw-users] electron coupling matrix / MLWF Hamiltonian

[Maxim Skripnik]

Hello gpaw users and developers,

is it possible to calculate the electron coupling matrix with GPAW 
without modifying the source code? Here is what I mean exactly:

Let ε be the electronic coupling matrix with

ε_mn = ∫ ψ*(x)_m H(x) ψ(x)_n dx

ψ(x) are the electronic states
H(x) = -ħΔ/2m + V(x) is the crystal hamiltonian with the effective 
potential V(x)

m=n: on-site energies
m!=n: electron transfer integrals

Here, the wave functions are represented in direct space. In principle, 
I could use MLWF. This is possible with ASE. Then, I would also need the 
Hamiltonian in the MLWF representation.

So the more precise question is: Is it possible to get the Hamiltonian 
in the MLWF representation along with the MLWF? If yes, how? If not, can 
the code be modified with little effort?

Many thanks!