An issue about the "reorder" of the orbitals.

[Mhmd Al ahmad]

Dear Dirac users

I wanted to perform calculations for systems in "unusual" excited states. As I understand it, this requires conducting a "preliminary calculation" to build the orbitals and then reordering them based on the priority of filling them with electrons.

i) I ran a calculation for the hydrogen-like radon atom as a preliminary step. I reordered the orbitals to fill the 6s orbital (the  30th orbital in the hydrogen-like radon atom) instead of the 1s orbital. I calculated the radius of the 6s orbital and found it to be 0.33 Å.

ii) In the second case, I performed a calculation for the radon atom as a preliminary step and reordered the orbitals so that the 6s orbital (the  21st orbital in the radon atom) was filled first, adjusting the occupancy to account for one electron in the atom. In this case, I found the radius of the 6s orbital to be 0.77 Å.

Also, the two procedures produced different results for the 5s orbital, but I obtained the same results for the 1s, 2s, 3s, and 4s orbitals. I wonder why both procedures yielded the same results for the 1s, 2s, 3s, and 4s orbitals while providing different results for the 5s and 6s orbitals. 

Another question: Can we use Dirac to isolate Darwin's term from other relativistic contributions?


Best regards
Mohamed