THE $\nu_{2}$ and $2\nu_{2}-\nu_{2}$ BANDS OF $NO_{2}$: HYPERFINE RESONANCES IN THE (010) VIBRATIONAL STATE.

Abstract

High resolution Fourier transform spectra in the $720-920 cm^{-1}$ spectral region have been used to perform a re-analysis of the $\nu_{2}$ band vibrational transition) together with the first analysis of the $2\nu_{2}-\nu_{2}$ hot band of nitrogen dioxide. The spectra show that, for numerous $\nu_{2}$ lines, the hyperfine stucture is easily observable in case of resonances due to the hyperfine Fermi-type operator. By performing a full treatment of the spin-rotation and of the hyperfine operators, a new line list of the $\nu_{2}$ band (positions and intensities) has been generated: This synthetic spectrum is in excellent agreement with the experimental spectrum. Also a thorough analysis of the $2\nu_{2}-\nu_{2}$ hot band has been performed leading to an extended set of new (020) spin rotation levels. These levels, together with the {(100)(020)(001)} spin-rotation levels deduced previously from the analysis of the $\nu_{1} , 2\nu_{2}$ and $\nu_{3}$ cold bands ($6.3-7.5 \mu\,m$ spectral range) were least squares fit leading to a new set of vibrational band centers, rotational and spin-rotational and interaction constants for the {(100)(020)(001)} interacting states of $^{14}N^{1}\,^{6}O_{2}.$