Investigation of H-bonded media by means of Raman scattering in terms of the fractal formalism

1. Investigation of H-bonded media by means of Raman scattering in terms of the fractal formalism Maksymov A.O., Yakunov A.V., Bily M.M. National Taras Shevchenko Univ. of Kyiv, Physics Department, Ukraine

3. Comparison with amorphous media The most similar state is amorphous one. It shares condensed and irregular features of liquid. In every moment of time liquid can be represented as amorphous medium. It seems to be dynamically blurred amorphous network.

4. Percolation model However the molecular arrangement is compact the topology of hydrogen network is tracery. Owing to specific symmetry of each molecule and thermal molecular motions some of H-bonds are broken.

5. Fractal dimensionality d=2 – Euclidian dimensionality Medium behaves like homogeneous . d<2 – Hausdorf dimensionality Medium behaves like a fractal . The total area covered by cluster scales like ξ powered :

8. Crossover ξ The right sketch illustrates typical reduced Raman scattering spectrum that consists of the phonon and the fracton regions. The structure inhomogeneity size which is designated as correlation length ξ shown left is inversely proportional to the crossover frequency which separates fracton region from the phonon one.

12. Initial spectra The obtained Raman spectra of pure H-bonded substances are presented left. This spectra are reduced and presented right in log-log scale.

13. The information about the σ -exponent by itself is not useful since we have too many unknown parameters to make any conclusions about the structural dynamics of the investigated media. But the comparison may result in something more informative. Including of the molecule of another sort into the hydrogen-bond network leads to the structural rearrangement of medium and changes it’s features.

15. Discussion The fractal dimensionality in the most general form could be expressed as the function of the binary solution concentration: Here and are the numbers of potential H-bonds per molecule for the molecules of the first and the second sort accordingly; is the binary packing parameter for a given concentration of the molecules of two sorts. This parameter reflects the result of different molecule mixing.