Two-site "tight-binding model"

[amjad-sh]

Hello,
I've been asked to compute the time-resolved RIXS spectrum for an electron on a two-site "tight-binding model" in the presence of a strong electric field.
What it is meant by the term two-site here? does it mean a system of one electron and just two atoms?
Thanks

 

[rkkyjw]

Hi,
I guess here two-site means, in the unit cell there are two atomic orbitals at different sites, which constitute the basis of TB model. After diagonalizing the TB hamiltonian, you will get two bands. One electron means the unit cell only contains one electron. In the other words, electrons only occupy the lower bands of two bands (suppose there is a gap between two bands). A typical example I can think of is two band model of graphene. Hope it helps!