Spin-orbit coupling convergence equations

Using all the above, Cizek presents the explicit, spin orbital and spin-adapted CC doubles equations (CCD) i.e., T = T2 (then called coupled-pair many-electron theory) in terms of one- and two-electron integrals over an orthogonal basis set. Assisted by Joe Paldus with some computations, he also reports some CCD results for N2, which though limited to only ti to Ug excitations, uses ab initio integrals in an Slater-type-orbital basis. He also does the full Cl calculation to assess convergence, a tool widely used in Cizek s and Paldus work and by most of us, today. He also reports results for the minimum-basis TT-electron approximation to benzene. 

At convergence of the spin-coupled minimisation procedure, the orbitals satisfy equations which can be recast in the form [4]... 

At convergence of a single-configuration spin-coupled calculation, the active orbitals equations based on (A-l)-electron operators from which the particular occupied orbital has been excluded (9) ... 

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