Experiment nr. 5

Rotation-vibration Spectra of Molecules

Supervisor:  Dr. Volker Riede

The investigation of rotation-vibration spectra is done on a diatomic molecule (HCl). The theoretical treatment is done in the framework of quantum mechanics with help of the so-called “dumbbell” model. The interaction of the oscillator and the rotator is included. Due to the precision and the spectral resolving power of the spectrometer it is possible to measure the rotational constant in dependence on the vibrational quantum number. Besides the influence of the chlorine isotopes on the spectrum may be investigated. The dependence of the intensity of the lines on the wave number has to be calculated for the interpretation of the Bjerrum´s double bands. The parameters of the used spectrometer (resolving power, stray light) have to be determined.