Knowledge Bank

This work continues a series of publications devoted to the application of the effective operators approach to the analysis and prediction of vibration-rotation spectra of linear triatomic molecules. In that frame, the present work aims at describing line intensities of cold and hot bands of $\mathrm{<mrow\; data-mjx-texclass="ORD">14</mrow>}N216O$ in its ground electronic state in the spectral range above $3600cm-1$. In $N2O$, vibrational interacting levels group in polyads, identified by the so-called polyad number $P=2V1+V2+4V3$, as a result of the relation $2\omega 1\sim 4\omega 2\sim \omega 3$ existing between the harmonic frequencies. The absorption spectra of $N2O$, at room temperature, have been recorded in Brussels over the whole range between 3600 and $11000cm-1$ using a Bruker IFS120HR Fourier transform spectrometer. The measurement and analysis of absolute line intensities in the region between 4300 and $5200cm-1$, involving bands associated with transitions corresponding to $\Delta P=7,8$ and 9, was done $recently.a$ We are now measuring absolute line intensities for cold and hot bands associated with transitions corresponding to $\Delta P=10$ and 11, observed in the range from 5200 to $6400cm-1$. Using wavefunctions previously determined from a global fit of an effective hamiltonian to about 18000 line $positions,b$ parameters of a corresponding effective dipole moment are then fitted to these experimental intensities. Results will be presented and discussed.