Knowledge Bank

We determine absolute ro-vibrational line intensities for $\Delta V=1(V=1-4)$ vibrational bands of the astrophysically important species. NH, indepently of any information on its molecular concentration. To this end we measure relative line intensities across $\Delta V=1$ bends. The effect of vibration rotation interaction on the line intensities then allows a direct determination of the derivative of the electric-dipole fundamental band transition $moment1$. The results of these experiments are then compared to theoretical $calculations2$ obtained via high quality ab initu calculations of the electric dipole moment function.