A MOLECULAR MODEL POTENTIAL STUDY OF THE HOMO–LUMO GAP IN A LOW-DIMENSIONAL CRYSTAL

We study the effect of some crystal vibrations on the electron distribution and the gap HOMO–LUMO in a linear chain of atoms where, the valence electrons move in a model potential constructed by combining atromic boxes. It is found that at the turning points, these two levels collapse together for a chain with an even number of atoms while for a chain with an odd number of atoms these two levels never touch each other.

The effect of some asymmetric crystal vibrations on the electron density distribution and the gap HOMO–LUMO is also analyzed for a low-dimensional solid whose repeating unit consists of a square arrangement of atoms where the valence electrons move in a CAB model potential.