Enhancement of low energy phonon structure by high energy spectral weight

We have investigated the effect on the tunneling characteristics of adding weight to the electron phonon spectral density α²((ω)F(ω) at an energy ω_E well above its cut off ω_D. This not only adds structure in the current (I) as a function of voltage (V) at ω_E but more importantly enhances the structure below ω_D although no addition to the strength of the spectral density is made in that region.