Electron energy spectrum of ice

For the first time the tight-binding model and the recursion method are used to study the electron energy spectrum of hexagonal ice (${\mathit{I}}_{\mathit{h}}$), which is characterized by disorder in its protonic subsystem. It is shown that, if the ice rules are fulfilled, the local density of states (LDOS) does not depend upon the proton configuration, but the violation of ice rules results in the strong disturbances of LDOS. Electron energy spectra of ${\mathrm{H}}_3$ ${\mathrm{O}}^{+}$ and ${\mathrm{OH}}^{\mathrm{-}}$ ions are also calculated.