Spectral optical constants of ethanol and isopropanol from ultraviolet to far infrared

• Optical constants of fluids (k, n) are required for many applications.
• For liquid ethanol and 2-propanol, the optical constant k is experimentally obtained.
• The extremely wide range of knowledge of k allows the use of the Kramers-Kronig theory.
• An ad-hoc technique of extrapolation allows to avoid truncation errors on n.
• Limitations and tricks of this approach are discussed.

Ethanol and isopropanol are fluids of common use in different branches of materials science. In particular, in the ever growing field of nanoscience, they are dispersing media for nanoparticle suspensions. The knowledge of optical constants of these fluids is required for the characterization of optical properties of nanoparticles, besides providing insights into fundamental properties of fluids themselves. In this work, we calculated the real refractive index n of ethanol and isopropanol applying the Kramers-Kronig theory to the experimentally obtained k spectrum over an extremely wide spectral range, from 181 to ∼ 54000 cm−1.