Date of Award
Pure sciences, Coupling strengths, Helium-3, Hyperfine transitions
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The hyperfine structure of 3He with an external magnetic field is precisely calculated by using double basis set wave functions. The comparison with available experiments effectively tests the theory of hyperfine structure.
An exact diagonalization provides a comprehensive interpretation of the results across the complete range of hyperfine coupling strengths of 3He. The theoretical investigation shows that suppression of the hyperfine transitions is caused mainly by strong hyperfine mixing and accidental cancellation between two hyperfine states. An IS coupling model can also qualitatively interpret the suppression of the hyperfine transitions. However, this work has shown that the IS model will become more accurate as the hyperfine transitions occur between 23S1 and n 3PJ states with higher values of principal quantum number n.
An unexpected result of this work is that even for the low-Z isotope 3He, hyperfine-induced transitions are still important. This originates from strong hyperfine mixing between singlet and triplet states.
Wu, Qixue, "Hyperfine structure and hyperfine transitions of helium-3" (2009). Electronic Theses and Dissertations. 8081.