Problem calculating SLA doped with Eu

[Kousei]

Hello Everyone,

I am trying to replicate a paper: First-principles study of the luminescence of Eu2+-doped phosphors by Jia et al.
The transition energies of SLA:Eu2+ were calculated.

The procedure is as follows:
1. structurally relax the matrix
2. create a supercell and determine the stable structure and the total energies of the ground and excited states
3. perform a single point calculation of the ground and excited states using the stable structure to determine the total energies
4. calculate the transition energies from the difference in total energies.

As a result, the transition energy shown in the paper is about 2 eV, whereas my calculation is much larger, about 8 eV. The plotted band diagram also differs significantly from the paper.
How can I interpret the cause of this?

Best regards.

[Kousei]

I have not been able to verify this yet due to lack of time, but I have come to the conclusion that the order of the orbitals may be swapped due to a subspace diagonalization when calculating the excited states.
I will change the algorithm and try to calculate with LDIAG=.FALSE.
I will report the results in this thread.
Thank you very much.