Christiansen-Lee-Pitzer method

Fig. 2. A comparison of dJoiine 3s pseudo-orbitals generated with the Christiansen-Lee-Pitzer method and the Phillips-Kleinman pseudo-orbital and the all-electron Hartree-Fodc orbital.

The two regions of the orbitals are matched at a matching radius, so that the derivatives are continuous at this radius. The shape-consistent pseudo-orbital is defined in the Christiansen-Lee-Pitzer method as... 

Figure 2 compares the pseudo-orbitals obtained from the shape-consistent Christiansen-Lee-Pitzer method with the Phillips-Kleinman, and the all-electron techniques for the chlorine 3s orbital. As seen from Figure 2, the maximum of the pseudo orbital obtained from the Phillips-Kleinman method, occurs at a shorter distance, compared to both the Christiansen-Lee-Pitzer orbital and the all-electron 3s Hartree-Fock orbital of the chlorine atom, which is the origin of under-estimation of the repulsive wall of the potential surface in the Phillips-Kleinman method. Furthermore, the shorter maximum in the Phillips-Kleinman method leads to shorter equilibrium bond distances using the Phillips-Kleinman potentials. 

Ermler, Christiansen, and co-workers have generated analytical Gaussian forms for both the averaged RECPs and spin-orbit operators, derived using the Christiansen-Lee-Pitzer method. The ECPs were fitted into Gaussians as in equation (39) ... 

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See also in sourсe #XX -- [ , ]

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