What is Fluorescence Spectroscopy?
Molecules have various energy levels. Fluorescence spectroscopy relates to electronic state and vibrational states. It has a ground & excited electronic state, the ground electronic state has a lower energy level, excited electronic state has a higher energy level, various vibrational lies between higher and lower energy.
In fluorescence, the material is excited by absorbing a photon from its ground electronic state to one of the various vibrational states in the excited electronic state. Molecules collisions cause the excited molecule to lose vibrational energy then it drops down to the lowest vibrational state of the excited electronic state. When the molecule drops down one of the various vibrational levels of the ground electronic state, it emits a photon. Because molecules can drop down into any of several vibrational levels in the ground state, the emitted photons will have different energies and frequencies. Therefore, Through analyzing the different frequencies of light emitted in fluorescent spectroscopy, along with their relative intensities, the structure of the different vibrational levels can be determined.