Spectra of polyatomic molecules

Theory of molecular spectra

Figure 1 - Interatomic potential (nuclear and electronic contributions)

Figure 2 - Energy level diagram of a homonuclear diatomic molecule

Figure 3 - Lower electronic states of the O 2 molecule

Figure 4 - Vibrational energy of a diatomic molecule. Vibrational energy levels and associated wave functions

Figure 5 - Rotation of a diatomic molecule with angular velocity about an axis passing through the center of mass C

Figure 6 - Angular momentum coupling for Hund&#039;s a and b cases

Figure 7 - Rotation-vibration belt

Figure 8 - Fortrat&#039;s parable

Figure 9 - Population distribution in the different vibrational levels of molecule I 2

Figure 10 - Population distribution on different rotational levels and resulting spectrum for different temperatures

Figure 11 - Electronic transition giving a band spectrum

Figure 12 - Illustration of the Franck-Condon principle. Associated spectra

Figure 13 - Absorption on a continuum

Figure 14 - Predissociation in the case of the A ® X transition

Figure 15 - Water molecule

Figure 16 - Carbon dioxide molecule

Figure 17 - Fundamental vibrations of the carbon dioxide molecule

Figure 18 - Partial diagram of the energy levels of the CO 2 molecule.

Figure 19 - Iodine vapor absorption transitions

Figure 20 - Fluorescence transitions of iodine vapour

Figure 21 - Jablonsky diagram

Figure 22 - Raman scattering

Figure 23 - Hot bands in Raman spectra

Figure 24 - Rotational Raman spectrum

Figure 25 - Raman rovibrational spectrum of the N2 molecule.