Radio waves | Microwaves | IR | Visible | UV | X-rays | g-rays |
nuclear spin orientation in magnetic field | electron spin orientation
| molecular vibration and rotation | excitation of valence electrons | excitation of middle and valence shell electrons | excitation of K and L shell electrons | nuclear fission and fusion |
Application in NMR spectroscopy | Application in ESR spectroscopy | Application in IR spectroscopy | Application in colourimetry | Application in UV spectroscopy | Application in X-ray crystallography | nuclear reactors |
Energy falling on a molecule is used for executing various kinds of motion by the molecule:
1. Translation: The molecule as a whole moves from one location to another.
2. Rotation: The molecule rotates about its centre of gravity around various axes.
3. Vibration: Atoms in the molecule can vibrate ie. they can change their position relative to other atoms in the molecule. There are different kinds of vibrations like symmetrical stretching, unsymmetrical stretching, scissoring, rocking, wagging and twisting.
4. Electronic transitions: Electrons move from one energy level to another inside the atoms.
5. Electron spin changes.
6. Nuclear spin changes.
The energy required for the various transitions are different. The total energy possessed by a molecule is the sum of all the different energies required for the various kinds motions described above.