Question

16. The following transitions could occur in an octahedral d complex: ii A2gTu iv. A2gE V. Which of these are formally forbidden and why? V Make an order of magnitude estimate of the extinction coefficient of each transition. a. b.

Answer 1

ThoSe transitions are allowed for which the spin multiplicity is same. I.e from same spin state to other same spin state

2) Also g to g or u to u transition are not allowed but g-->u or vice versa is allowed.

So based on this we see

I) Allowed - as spin multiplicity is same and also it is from g --> u

ii) Not allowed because it involves g to g

iii) Allowed

iv) Not allowed

v) Not allowed as spin multiplicity is not same .

B) Those traditions which are allowed have high magnitude of extinction coefficient may be of the order of 10^5 or more

And for forbidden transition it is less than 10^3 lies between 1 to 1000 or less .