Determination of N-N and N-O S-branch Raman linewidths using time-resolved picosecond pure rotational coherent anti-Stokes Raman scattering.

- and - S-branch Raman linewidths have been determined using picosecond dual-broadband pure rotational coherent anti-Stokes Raman scattering (CARS). Time-resolved rotational CARS measurements were performed in gas-phase and air for temperatures up to 1900 K in order to determine the time constants of the coherence decay to subsequently calculate the S-branch Raman linewidths. Coherence decay time traces and the resulting S-branch Raman linewidths are presented for - and - collisions. Therewith, we reduce the gap of widely missing S-branch linewidth data in the temperature regime of many combustion processes. Further, we demonstrate that the standard monoexponential fitting of the coherence decay, as it is commonly done for nitrogen, is not applicable to oxygen.