  In addition to the ubiquitous structural relaxation of viscous supercooled
liquids, monohydroxy alcohols and several other hydrogen-bonded systems display
a strong single-exponential electrical low-frequency absorption. So far, this
so-called Debye process could be observed only using dielectric techniques.
Exploiting a combination of broad-band and high-resolution rheology experiments
for three isomeric octanols, unambiguous mechanical evidence for the Debye
process is found. Its spectral signature is similar to the viscoelastic
fingerprint of small-chain polymers, enabling us to estimate the effective
molecular weight for the supramolecular structure formed by the studied
monohydroxy alcohols. This finding opens the venue for the application of
further non-dielectric techniques directed at unraveling the microscopic nature
of the Debye process and for an understanding of this phenomenon in terms of
polymer concepts.
