Abstract book - Prof. Per Jensen, Ph.D. - Bergische Universität ...

Poster session, H38 151Laser magnetic resonance of NO 2 molecules: line positions andintensitiesAsylkhan Rakhymzhan and Alexey ChichininInstitute of Chemical Kinetics and Combustion, Russia, chichinin@kinetics.nsc.ruRakhymzhan A.Chichinin A.Laser magnetic resonance (LMR) spectra of the 2 fundamental band (010 000) ofNO 2 in the perpendicular polarisation (E B) are recorded in the 884—982 cm -1 rangeand analysed for all available 13 C 16 O 2 and 12 C 16 O 2 -laser frequencies. The analysisincludes assignment of the observed transitions and calculation of the LMR linestrengths for both polarisations. As a result, we predict the strongest spectra, whichnormally are unresolved. Such unresolved overlapped spectra are normally useless formolecular parameters determination, but they are very useful for applications. In otherwords, we would like to have calibrated absorption, which is necessary for ourintracavity setup to determine absolute absorptions by other gases. Note also that theorigin of the 2 band is 750 cm -1 , hence the intensities of the LMR spectra should bevery sensitive to the temperature of the gas mixture which contains NO 2 . Hence we planto use the LMR spectra to determine the temperature of the gas mixtures.In the literature there is a single LMR study 1 in which line positions measurements inE║B polarisation and analysis of the 2 band are reported. However, the analysis havenot included the line intensities, unresolved spectra, and transitions with N>17.A typical example of our experimental unresolved LMR spectrum is shown at fig. 1A. Itis a clear example of a-a transition: the shape of the spectrum depends only onbroadening factors and on the F 2 ''–F 2 ' transition frequency. The structure of thespectrum is shown at fig. 1C. It consists of series -8.5M J '' 4.5 transitions, all of themoriginate from 11 9,3 12 10,2 rotational transition. Smooth curve at fig. 1C presentsabsorption cross section dependence on magnetic field (B), and the derivative of thecurve / B is presented at fig. 1B.References[1] K. Hakuta and H. Uehara, J.Molec. Spectr., 94 (1982) 126-135