Boris N. Plakhutin

Koopmans’s theorem in the restricted open-shell Hartree–Fock method. II. The second canonical set for orbitals and orbital energies

A treatment of the validity of Koopmans’s theorem (KT) in the restricted open-shell Hartree–Fock (ROHF) method can be separated into two essentially different cases. The first of them involves the one-electron processes X→Xj± in which the spin state of an ion Xj± having a hole or an extra electron in the closed, open or virtual orbital ϕj is correctly described by a one-determinant wave function. This case was analyzed using different methods by Plakhutin et al. [J. Chem. Phys. 125, 204110 (2006)] and by Plakhutin and Davidson [J. Phys. Chem. A 113, 12386 (2009)]. In the present work we analyze more complex processes where the state of an ion cannot be described by a single determinant. An example of such processes is the removal of an alpha electron from the closed shell of a high-spin half-filled open-shell system X. For this case we give a slightly generalized formulation of KT in both the “frozen” orbital approximation (i.e., within the canonical ROHF method) and the limited configuration interaction ...

General form of the total one-electron Hamiltonian in the restricted open shell Hartree-Fock method

The structure of the effective one-electron Hamiltonian

Spectrum of states in icosahedral structures with gN electronic configuration (n = 1– 7). 2. Ab initio calculation of the c20 (I h) molecule and its anions

\hat R

Koopmans’ theorem in the Hartree-Fock method. General formulation

in the Hartree-Fock equation

Structure and stability of the SiH3O2: Radical

\hat R \varphi _i = \varepsilon _i \varphi _i

On the position of the nitrogen 2p energy level in endohedral N@C60 (Ih)

is discussed in many works. The most general definitions of