Disordered 2D excitons

These surface excitation phenomena are investigated in this section, on excitons in the intrinsic-surface-bulk system, and the next section, on disordered 2D excitons. 

We combine now the disordered part (4.3) with the retarded part of (4.1), which does not depend on the particular resonance energy of one domain or site, but on the transition dipole operators, and therefore is identical for our model to that of the perfect 2D lattice. Thus, we obtain the following effective hamiltonian for the disordered 2D exciton ... 

---