Question

Spectroscopy involves techniques that can identify substances and determine their concentrations. Identify the atomic or molecular processes associated with the UV/visible and microwave regions of the electromagnetic spectrum and explain how they arise.

Answer 1

when electromagnetic radiation interacts with matter a variety of phenomena may occur , in that

Atomic absorption of electromagnetic radiation: when atom absorb electromagnetic radiation, this results in an increase in their electronic energy which leads to jumping of electron from inner orbit to any outer orbit.When the excited atom reverts to the ground state from exicited state, it loses energy in one straight jump or through a number of steps in the form of single quantum or photon of elctromagnetic radiation..When it happens for a large number of atoms, the total effect is shown in the light spectrum as a spectral line.

molecular absorption of electromagnetic radiation: when molecule absorbs electromagnetic radiation, it gets excited and when it returns to the ground state, it emits bands which are charecteristics of the molecule concerned and each band is composed of large number of very fine lines.

The above processes are associated with uv/visible spectrophotometry

Microwave spectroscopy , the spectrum results from transitions between the rotational energy levels of a gaseous molecule on the absorption of radiation falling in the microwave region( 1-100 cm^-1)