Together with the electronic states, the vibrational states were also shown to form bands.

Both are used to measure the energy required to change the vibrational state of a chemical compound.

This is because initially very few molecules are in excited vibrational states compared to the number in the ground state.

Fluorescence spectroscopy is primarily concerned with electronic and vibrational states.

Within each of these electronic states are various vibrational states.

This drives the ground and the vibrational states of the molecules to change in a synchronized fashion.

The molecules in the vibrational state are then strongly driven back into the ground state.

By hitting the molecules with enough light, we spread the population over many vibrational states and, eventually, the populations equalize.

There are many more rotational states in a given molecule than vibrational states.

The molecule is excited to another electronic state and to many possible vibrational states .