Question

In an experiment, it is seen that an electric-dipole (E1) transition can connect an initial nuclear state of spin-parity \( J_i^\pi = 2^+ \) to a final state \( J_f^\pi \). All possible values of \( J_f^\pi \) are

• A. \( 1^+, 2^+ \)
• B. \( 1^+, 2^+, 3^+ \)
• C. \( 1^-, 2^- \)
• D. \( 1^-, 2^-, 3^- \)

Hint:

In E1 transitions, the parity must change, and \( \Delta J = \pm 1 \).

Answer 1

The Correct Option is D

Step 1: In an electric dipole (E1) transition, the change in angular momentum \( \Delta J = \pm 1 \) and parity also changes (since \( \Delta \pi = \pm 1 \)).

Step 2: For an initial state with spin-parity \( J_i^\pi = 2^+ \), the allowed transitions must obey the selection rules. The final spin \( J_f \) values can be \( 1^-, 2^-, 3^- \), because the parity must change from \( + \) to \( - \). Thus, the possible values are \( 1^-, 2^-, 3^- \).
Thus, the correct answer is (D).