Nesbet

Nesbet R K 1963 Computer programs for eleetronie wave-funetlon ealeulatlons Rev. Mod. Rhys. 35 552-7... 

Nesbet, R K 1965 Algorithm for diagonalization of large matriees J. Chem. Rhys. 43 311-12... 

The Roothaan equations are the basic equations for closed-shell RHF molecular orbitals, and the Pople-Nesbet equations are the basic equations for open-shell UHF molecular orbitals. The Pople-Nesbet equations are essentially just the generalization of the Roothaan equations to the case where the spatials /j and /jP, as shown previously, are not defined to be identical but are solved independently. 

As seen in Section 3.5, the Roothaan-Hall (or Pople-Nesbet for the UHF case)... 

Butler, W.H., and Nesbet, R.K., 1990, Validity, accuracy, and efficiency of multiple-scattering theory for space-filling scatterers, Phys. Rev. B 42 1518. 

Nesbet, R. K., Pyoc. Roy. Soc. London) A230, 312, 322, "Configuration interaction in orbital theories." "Excited electronic states of 1,3-butadiene."... 

In the unrestricted treatment, the eigenvalue problem formulated by Pople and Nesbet (25) resembles closely that of closed-shell treatments.-On the other hand, the variation method in restricted open-shell treatments leads to two systems of SCF equations which have to be connected in one eigenvalue problem (26). This task is not a simple one the solution was done in different ways by Longuet-Higgins and Pople (27), Lefebvre (28), Roothaan (29), McWeeny (30), Huzinaga (31,32), Birss and Fraga (33), and Dewar with co-workers (34). 

The methodology presented here expands the recent CASPT2 approach to more flexible zeroth-order variational spaces for a multireference perturbation, either in the Moller-Plesset scheme or in Epsein-Nesbet approach [70-72]. Furthermore, it allows for the use of a wide set of possible correlated orbitals. These two last points were discussed elsewhere [34]. 

In the present paper, we propose the use of the HPHF approximation for the direct calculation of excited states, in which M5=0,just as Berthier [11], and Pople and Nesbet [12] did for the determination of states in which Ms 0. We give some examples of such calculations, either when the excited state wavefunction is orthogonal or not by symmetry to that of the ground state. 

Molecules and Atoms, Electronic Correlation in (Nesbet) Molecules and Atoms, Electronically Excited, Collisions of (Muschlitz). ... 

Most of these developments may be applied most directly within the framework of the isolated molecule method, in which the reactivity indices are the charges and self-polarizabilities of the unperturbed ground state of a given molecule calculations based on the localization model (e.g. Nesbet, 1962) have made less progress, and will not be considered. It is therefore natural to enquire whether indices similar to and tt,, in Hiickel theory can still be defined, and calculated more precisely, in self-consistent field theory. The obvious questions are... 

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