Question

discuss combination band with one example ​

Answer 1

Answer:

mixture bands are located while greater than or extra essential vibrations are excited simultaneously. One motive a aggregate band might arise is that if a essential vibration does now not occur because of symmetry. this is akin to vibration coupling in electronic transitions wherein a fundamental mode may be excited and allowed as a “doubly excited kingdom.” combination implies addition of two frequencies, but it additionally feasible to have a distinction band where the frequencies are subtracted.

To decide if two states can be excited simultaneous the transition moment imperative ought to be evaluated with the suitable excited country wave function.

consider an example in the transition

Ψ'(0)Ψ^2(0)Ψ^3(0)→Ψ^1(2)Ψ^2(0)Ψ^3(1)

here the symmetry of the excited state will be the direct product of the irreducible representation for Ψ1(2) and Ψ3(1)