In cooperation with the ODEE laboratory of Hochschule Darmstadt, high resolution Raman spectra are measured at higher temperatures and elevated pressures. The spectra are fitted to simulated Raman spectra to both validate the theoretical models as well as to determine species concentration and temperature. The simulation of Raman spectra is done by the RAMSES code (RAMan-Scattering Experiment Simulator) which is continuously being updated and advanced. Additionally, fitting algorithms must be created to account for background illumination, overlap of spectral features of different species (cross talk) and other interferences. Effects of higher pressure like spectral broadening, spectral shift and non-linear change of the Raman cross sections need to be examined, implemented in the simulating code and validated experimentally.