Knowledge Bank

The high temperature Raman spectra of $H2O$ and $CO2$ have been measured and compared with theoretical models. The spectra were recorded using a rapidly pulsed frequency doubled Nd:YAG laser with gated photon counting and multiple spectrometer scans. The samples were in the post flame gases of a surface mixing burner which allowed control of gas conditions over a wide range. The $CO2$ spectra can be explained using existing molecular constants, but the $H2O$ spectrum requires the use of tables of energy levels, which are incomplete. In particular, this means that the partition function cannot be calculated exactly. Deviation from the classical partition functions will be discussed.