Using atomic coordinates of amorphous silicon structures generated by molecular dynamics simulations, we have calculated total cluster energies together with orbital energies and wave functions for representative dangling-bond and floating-bond sites. The ab-initio unrestricted Hartree-Fock cluster method was employed to describe the electronic structure of the corresponding a-Si clusters. We have found that the dangling bond state is energetically much more favourable than the floating bond state. Our results for the wave function confirm that the dangling bond wave function tends to be more localized compared to the one of the floating bond. We have also examined the sensitivity of the eigenstates and eigenvalues to external conditions for both cases.