1. Dr. Pandit Khakre
Asst. Prof
Mrs. K.S.K. College, Beed

2. Electronic spectra of transition metal complex :
The complex of the transition elements are highly coloured compounds.
Eelctronic transition occour when electron with in the molecular or ion move from one energy level to another.
Electronic ground state to electronic excited state. They by absorption bond is observed.
Definition : the promotion of electron from an orbital at lower energy to an orbitals of higher energy due to obsorption of electromagnetic radiation causes a change in arrangement of electron in orbitals of the molecule is known as electronic transition.

3. Types of Electronic transition :
d-d transition.
Ligand to metal charge transfer transition.
Metal to ligand charge transfer transition.
Inter ligand transition.

4. Spin selection rule :
The transition in which tehre is no change in spin of electron in going from lower to higher energy state called spin allowed transition.
Such transition s = 0 transition s is not equal to 0.
In case Mn2+ in a weak field. Octahydral complex like the d-d transition are spin forbidden.
Spin forbidden transition are very weak than spin allowed transition.
s = 0 allowed transition.
s = 0 forbidden.
Triplet triplet doublet doublt
3T1g T1g Eg T1g
3T1g A2g singlet singlet

5. Orbital selection rule / laporte selection rule :
Transsition with in a given set p or d orbital are termed as orbital selection rule or laporte forbidden
The transition dE1 dro dE0 dr1
That takes places [Ti (CH2O)6]3+ is laporte forbidden.
Completely allowed electronic transition generally etlinetion coefficients of the order of 103 to 105 molecule with center of symmetry.

6. Orgel energy level diagram for octahydral complex of ion with d1
configuration :
To construct a correlation diagram for each electronic configuration in the series d1 for both octahydral.
All terms of multiplicity other than that of ground state can be energy level.
The energy level order of the states arising the splitting of terms state of dn log P orticular field opposite that for do-n ion in same field.
The splitting of the 2D level into high energy level (eg) and low energy level (t2g)
Ground term symbol D split into two symbol T2g an0 Eg. 2T2g or 1 eg which gives rise to 2Eg.

7. Orgel diagram for D5 configuration :
The two low energy quartel term for the construction of an energy level diagram.
The higher energy doublet term the d5 configuration yield 4G4F4D and 4P as the quortet terms.
4G is first exited and lowest terms in which 4G lies as the first excited term and the actual order is 4G<4P<4D<4F.
In terms interaction is the order T>E>A the 4A1g and 4Eg are shown in d em is parallel lines.
6A19 are said to be accidently degenarate under octahydral crystal field.

8. Orgel diagram for D9 configuration :
The ground state term is 2D for d9.
The diagram for a d9 configuration which gives rise to 2D term the ground state.
The splitting of the energy states of horizontal axis as shown in figure.
The energy level with the g subscripts corresponds to octahedral complex which have central of symmtry.
The number and nature of electronic transition that occour in the absorption sectra of the complex with d9.
The energy corrsponds to the seporation of nEg and nT29 levels.