Discuss the three basic types of molecular spectroscopy

$-$ Rotational $($microwave$)$ spectroscopy

$-$ Vibrational $($infrared$)$ spectroscopy

$-$ Electronic spectroscopy $($Ultraviolet$-$Visible$)$ :

$$Theoretical background in terms of models and principles involved $($e$.$g$.,$ the rigid rotor harmonic oscillator, and Franck$-$Condon principle$),$ the separation of energy levels and the selection rules.

$$ The conditions for each types of spectroscopy and the types of molecules involved with examples.