The microwave spectrum of nitrogen dioxide and chlorine dioxide
Baird, James Clyde, Jr
Doctor of Philosophy
The two molecules nitrogen dioxide and chlorine dioxide present an intriguing array of energy levels for the spectroscopist to unravel. When considered as a rigid molecular frame the molecules possess rotational levels characterized by the usual asymmetric rotor theory. Nitrogen dioxide has been discussed from this point of view and complete structural parameters have been determined. However, these relatively simple rigid rotor levels are split by the effects of the magnetic moments of the unpaired electron and the nuclear spin. Therefore, the microwave spectrum is more complex than expected from the rigid rotor point of view. Ordinarily, one would expect a removal of the two fold degeneracy due to the electron spin and the 2I + 1 fold degeneracy from the nuclear spin. This arises because of the magnetic interaction between these spins and the field generated by the rotating nuclear frame. For nitrogen dioxide there is a six fold splitting of each rotational level and one would expect a group of transitions as depicted in Figure 3. Since analogous remarks hold for chlorine dioxide we shall only mention that eight fine structure levels will result from these interactions.