Line interference effects in the vibrational Q-branch spectra of N2 and CO

✍ Scribed by G.J. Rosasco; W. Lempert; W.S. Hurst; A. Fein

• Publisher: Elsevier Science
• Year: 1983
• Tongue: English
• Weight: 540 KB
• Volume: 97
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(83)80524-7

✦ Synopsis

Self-broadened (520-200 kPa) Q-branch spectra are measured by high-resolution cw-stimulated Raman spectroscopy. Line overlap in these spectra is described using a rela__ation matris fommkrn and a fustarder (in density) solution to the resulting equation is used to fit the data. The parameters of this model arc analyzed in terms of rates of rotational ener_w transfer. in the following we consider the problem of selfbroadening, line overlap, and coherent line mixing in the vibrational Q-branch spectra of Nz and CO. These spectral distributions are important because of their use for optical diagnostics of temperature and pressure in a wide variety of systems [ 11, e.g. flames, jet engines, internal combustion engines, wind tunnels, etc. The Q-branch spectra are measured by using the technique of cw-stimulated Raman spectroscopy [2] in which the two-photon Raman transitions give rise to resonances in the third order in electric field response of the medium. The frequency difference of two lasers co-propagating through the medium is adjusted to coincide with the spectrum of Raman transitions and power loss is detected in the higher-frequency beam. For two gaussian beams of parallel, linear polarization focused within the gaseous medium, the fractional change in power is [2]