Determination of Temperatures Using CH Radical Emission Spectroscopy

An improved Boltzmann plot method where the intensity is taken as the integral of the experimental spectrum within a special band for a cluster of a rotational line of R and Q branches is proposed. This method aims at deducing rotational and vibrational temperatures using CH radical A²Δ →X²Π band emission spectroscopy accurately. In addition, the data relative to the rotation lines of CH (A²Δ →X²Π) for both temperatures are assembled. The emission spectrum of CH (A²Δ →X²Π) at the inner cone of an acetylene-oxygen flame in a rich oxygen state is recorded and both of the temperatures are determined by the above-mentioned method. The values are recorded as 3141 K and 3097 K, for the rotational and vibrational temperatures, respectively. This result reveals that the equilibrium between the rotation and vibration states is achieved. A simple discussion for this method is also provided.