A further focus of our interests are highly porous silica gels, which show a not completely clarified flexible behavior. Although these gels are known for a long time, there are still a lot of questions to solve and a lot of problems to solve.
The central experimental methods used in the working group are the Raman and the Brillouin spectroscopy. Both are optical spectroscopy techniques with different resolving power in each case. Different systems of condensed matters are irradiated with laser light, which leads to excitation. As a result, a frequency shift is measured. With the Raman spectroscopy the frequency range of 10 cm-1 to 5000 cm-1 resp. the energy range of 0.001 eV to 0.6 eV is covered, which covers molecule and lattice vibrations. With smaller frequencies resp. energies (500 MHz to 30 GHz resp. 2 µeV to 120 µeV) the Brillouin spectroscopy is used, with which the propagation of high frequency acoustic waves (hypersonic) can be examined. For even lower excitation frequencies, ultrasonic and laser reflectrometry investigations are used.