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Two-center approximation

We, therefore, usually make the so-called two-center approximation for i / j ... [Pg.126]

C. Tight-Binding Models Beyond Two-Center Approximation... [Pg.651]

As Hamiltonian matrix elements 7/, in this basis are calculated within a two-center approximation [21]... [Pg.442]

A priori relativistic corrections to off-diagonal blocks in the Hamiltonian cannot be neglected. This problem has already been addressed in Ref. [665] in the framework of the so-called two-center approximation, in which the DKH... [Pg.554]

The formulation of the TEA up to this point has assumed that the TEA hamiltonian matrix elements depend only on two single-particle wavefunctions centered at two different atomic sites. Eor example, we assumed that the hamiltonian matrix elements depend only on the relative distance and orientation of the two atomic-like orbitals between which we calculate the expectation value of the single-particle hamiltonian. This is referred to as the two-center approximation, but it is obviously another implicit approximation, on top of restricting the basis to the atomic-like wavefunctions. In fact, it is plausible that, in the environment of the solid, the presence of other electrons nearby will affect the interaction of any two given... [Pg.138]

The Hamiltonian integrals and the overlap integrals are calculated with atom-centered localized atomic orbitals under a two-center approximation. These atom-centered orbitals are constructed by solving modified KS equations of spherical pseudoatoms with confinement potentials ... [Pg.422]


See other pages where Two-center approximation is mentioned: [Pg.176]    [Pg.222]    [Pg.179]    [Pg.310]    [Pg.879]    [Pg.653]    [Pg.662]    [Pg.683]    [Pg.694]    [Pg.696]    [Pg.278]    [Pg.443]    [Pg.158]    [Pg.163]    [Pg.164]    [Pg.165]    [Pg.223]    [Pg.555]   


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