question archive (a) Briefly describe the central-field approximation for many-electron atoms (in around 200 words)
(a) Briefly describe the central-field approximation for many-electron atoms (in around 200 words)
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(a) Briefly describe the central-field approximation for many-electron atoms (in around 200 words). Your answer should explain why this approximation predicts that atomic orbitals with the same pair of values of n and Ι, but different values of m, are degenerate. In the Coulomb model of a hydrogen atom, states with the same value of n but different values of Ι have the same energy. Explain why many-electron atoms do not exhibit this degeneracy. Give a qualitative argument indicating why atomic orbitals in a many-electron atom have energies that increase as Ι increases for any fixed value of n.
(b) A titanium atom has an excited-state configuratio
1s22s22p63s23p64s23d14p1
When residual electron–electron interactions are taken into account, this configuration splits into a number of atomic terms. List these atomic terms, labelled by their L and S quantum numbers, and also give each term an appropriate spectroscopic symbol. Outline your reasoning.
(c) Specify the degree of degeneracy of each atomic term in part (b) and confirm that the total number of states associated with all these atomic terms agrees with the number expected from the ` and s quantum numbers of the two valence electrons in the given configuration.
(d) When the spin–orbit interaction is taken into account in the LS-coupling scheme, the atomic term with L = 1 and S = 1 splits into a number of atomic levels. Label these atomic levels by their L, S and J quantum numbers, and give each level an appropriate spectroscopic symbol. Outline your reasoning.
