  The energy spectra of gravitational waves (GW) produced in quintessential
inflationary models increase in frequency and exhibit a sharp spike around 170
GHz where the associated fraction of critical energy density today stored in
relic gravitons is of the order of $10^{-6}$. We contrast our findings with the
spectra of ordinary inflationary models and we comment about possible
detetction strategies of the spike.

High Energy Physics - Phenomenology;Astrophysics;General Relativity and Quantum Cosmology