Module solver 

PM3 NDDO solver: builds Fock matrix, runs SCF, returns energies.

Implements the core PM3/NDDO workflow:

1. Build minimal basis (s for H, s+p for heavy atoms)
2. Compute overlap integrals using Slater-type approximation
3. Build core Hamiltonian from one-center and resonance integrals
4. Run restricted Hartree-Fock SCF with NDDO two-electron integrals
5. Return orbital energies, total energy, heat of formation

Structs

Pm3Result

PM3 calculation result.

Functions

solve_pm3

Run PM3 calculation on a molecule.