In this video I will explain the quantization of the 2 modes in which a gas molecule have energy that is quantized. I will explain the vibrational mode and the rotational mode. In the vibrational mode the difference between the energy levels is exactly the same. In the rotational mode the diatomic molecules can rotate about the z-axis (xy-plane) or x-axis (yz-plane) and the energy increases with the increase in energy levels.