Version 1 of the SCF code

In this chapter, Version 1 of the SCF code has been presented which will perform closed-shell or DODS single-determinant wavefunction calculations. The only reason why the code, as presented, will not perform GUHF calculations is because of certain properties of the equations, not the codes. The fact that the conventional one-electron Hamiltonian has no spin-dependent terms, together with the fact that one normally uses the eigenvectors of this one-electron Hamiltonian to form an initial il-matrix, means that there is no mechanism within the iterative procedure to induce a-fi mixing in forming optimum spin-orbitals. The GUHF orbitals will always turn out to be DODS in the absence of some explicit procedure to form orbitals which are linear combinations of basis functions of both spin types. 

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