pp hybridization

Dear all,

I would like to simulate the energy diagram of a system formed by a Cu ion with 10 3d states surrounded by 4 planar Oxygens that hybridizing their 2p states give birth to a band of 5 Ligand-P states with the same symmetry of the 3d levels. It is clear to me how to insert the hybridization between d and P the states but how about the pp hybridization?

In particular I would like to simulate the case in which, when the P-d hybridization is zero, omitting the crystalline field on the d states then the pp hybridization separates the p states into four levels with energies:

Ea1u = Delta_pd + Tpp
Eb1u = Delta_pd - Tpp
Eb2u = Ea1u
Eeu = Delta_pd

Schematically, at Tpd == 0, the energy diagram should be

d states

------- 5 3d states -------

P states

------- Ea1u, Eb2u -------

------- Eeu -------

------- Eb1 -------

I think that this is not right:

Delta_pd = -2.75 
Tpp = -1.0

Ea1u = Delta_pd + Tpp
Eb1u = Delta_pd - Tpp
Eb2u = Ea1u
Eeu = Delta_pd

Akm_pp = PotentialExpandedOnClm("Oh",1,{Ea1u,Eb1u,Eb2u,Eeu})
hybrid_pp = NewOperator("CF", NF, IndexUp_Ld, IndexDn_Ld, Akm_pp)
hybrid_pp.Name = "p-p hybridization"

Thanks in advance to all