[Zurück]

N. Kaun, J Baena, D. Newnham, B. Lendl:
"Terahertz pulsed spectroscopy as a new tool for measuring the structuring effect of solutes on water";
Poster: 3rd International Conference on Advanced Infrared and Raman Spectroscopy, Delavan, Wisconsin, USA; 14.08.2005 - 19.08.2005; in: "ICAVS 03", B. Lendl et al. (Hrg.); (2005).

Absorption spectra of aqueous solution of "chaotropes" (structure-breaker) and "kosmotropes" (structure maker) have been recorded in the mid-IR and terahertz (THz) spectral region. A different impact of the two groups of solutes on the absorption spectrum of water was found in the recorded THz spectra. A concentration dependent increased absorption across the investigated THz spectral region (0.04 - 2 THz , 1,3 - 66 cm-1 respectively) has been recorded for all studied chaotropic solutions, whereas the opposite has been obtained for kosmotrope containing solutions. In the case of ionic solutes a further increase in absorption towards higher frequencies was measured. The distinction between chaotrope and kosmotrope solutes was, as expected, also possible in the mid-IR spectral region. Depending on the structure forming effect of the solute the OH stretch vibration of the water (around 3400 cm-1) was slightly shifted. A red shift has been observed for solution of kosmotropes, whereas a blue shift was observed in case of solutions containing chaotropes. Compared to the mid-IR spectral region the structure influencing effect of solutes can be more efficiently studied in the THz spectral region, which provides information from interactions between neighboring water molecules.

http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC05937122

http://publik.tuwien.ac.at/files/pub-tch_4955.pdf