Light absorption in the UV region produces a change in the:
A
Rotational energy of molecules
B
Electronic energy of molecules
C
Vibrational energy of molecules
D
All three energies of molecules
Correct Option:
B
Explanation
Absorption of UV-visible radiation promotes electrons from lower to higher electronic energy levels. This contrasts nicely with other spectroscopic regions: microwave radiation primarily produces rotational transitions, while infrared radiation primarily excites molecular vibrations. Therefore UV spectroscopy is fundamentally concerned with electronic transitions.
