Bond and Lattice Dissociation Energies of NaH by RealQM

Let us now check if RealQM readily computes the bond dissociation energy in gaseous phase of the molecule NaH as separation into Na and H atoms, and the lattice dissociation energy in solid phase as separation into Na+ and H- ions. 

In stdQM this is viewed to be very difficult, if possible at all, which is not strange because stdQM is uncomputable (as we know). Instead, an empirical Born-Haber cycle is used. 

RealQM on the spot produces the following predictions in close agreement with reference values:

Bond dissociation energy =  E(Na) + E(H) - E(NaH)  = 0.08 Hartree  (ref 0.0765) (code) 

Lattice dissociation energy = E(Νa+) + E(H-) - E(NaH) = 0.38 Hartree (ref 0.307) (code) 

where E(X) indicates ground state energy of X, and in the code examples the distance (2*D in code) between atoms/ions is varied to capture separation while the number of iterations is kept the same for fair comparison. 

We see that the energy of a covalent bond without full electron transfer is much smaller than the lattice energy with full electron transfer from Na to H, naturally a consequence of different spatial "filling of electrons" in the sense of RealQM.  

In stdQM the mystery is deeper since the spatial presence of electrons is mysterious.