Term symbols

Reference,
https://en.wikipedia.org/wiki/Term_symbol
James E. Huheey, Ellen A. Keiter, Richard L.Keiter and Okhil K. Medhi, Inorganic Chemistry, Principles of Structure and Reactivity. 4th Edn. Pearsons

1. Spectroscopic Term symbols Mr. Mithil Fal Desai, Ph. D. Assistant Professor in Chemistry Shree Mallikarjun and Shri Chetan Manju Desai College Canacona , Goa T 2g E g A 2g T 2g T 1g T 1g (P) A 1g T 2 P D A 1 E T 1 S

2. 2 The term symbols are a symbolic representation of energy, angular momentum and spin multiplicity of an atom. For a Hydrogen atom it is defined as S, P, D, F states, depending upon the electron occupancy in s, p, d and f orbitals. Term Symbol

3. L 1 2 3 Ground term S P D F Components in octahedral field A 1g T 1g T 2g , E g A 2g , T 1g , T 2g Splitting of d n terms in an octahedral field 3

4. No. of d electrons l Orbital momentum Term Total spin (S) Free ion ground state Ground term in octahedral field Excited state term with same spin multiplicity 2 1 -1 -2 Σ l =L   Σ s=S 2S+1 2S+1 L 1 ↑ - - - - 2 D 1/2*1 2 2 D 2 T 2g 2 E g 2 ↑ ↑ - - - 3 F 1/2*2 3 3 F 3 T 1g 3 T 2g , 3 A 2g , 3 T 1g (P) 3 ↑ ↑ ↑ - - 3 F 1/2*3 4 4 F 4 A 2g 4 T 2g , 4 T 1g , 4 T 1g (P) 4 ↑ ↑ ↑ ↑ - 2 D 1/2*4 5 5 D 5 E g 5 T 2g 5 ↑ ↑ ↑ ↑ ↑ S 1/2*5 6 6 S 6 A 1g None 6 ↑↓ ↑ ↑ ↑ ↑ 2 D 1/2*4 5 5 D 5 T 2g 5 E g 7 ↑↓ ↑↓ ↑ ↑ ↑ 3 F 1/2*3 4 4 F 4 T 1g 4 T 2g , 4 A 2g , 4 T 1g (P) 8 ↑↓ ↑↓ ↑↓ ↑ ↑ 3 F 1/2*2 3 3 F 3 A 2g 3 T 2g , 3 T 1g , 3 T 1g (P) 9 ↑↓ ↑↓ ↑↓ ↑↓ ↑ 2 D 1/2*1 2 2 D 2 E g 2 T 2g Determination of term symbols 4

5. D T 2g E g F T 1g A 2g T 2g Splitting of ground terms by an octahedral field d 1 d 2 5

6. E g F Splitting of D term by an octahedral field T 2g T 2g E g d 1 and d 6 d 4 and d 9 2 D Dq Orgel diagram 6

7. T2g F A 2g T 2g Splitting of F term by an octahedral field T 1g T 1g d 2 and d 7 d 3 and d 8 Dq T 2g A 2g T 1g (P) (P) (F) T 1g (P) Orgel diagram 7