Hyperfine structure in ground multiplets of ¹⁷ O and ¹⁹ F

Abstract

The hyperfine structure coupling constants of the ground 3 P multiplet of 17 O have been measured in a paramagnetic resonance experiment with a sample of enriched oxygen gas. They are: a 2 = – 218.569 ± 0.004 Mc/s, a 1 = 4.738 ± 0.036 Mc/s, a 2,1 = –126.6 ± 2.0 Mc/s, a 1,0 = – 91.7 ± 7.2 Mc/s, b 2 = –10.438 ± 0.030 Mc/s, b 1 = 5.199 ± 0.090 Mc/s. These results confirm the values of a 2 and b 2 reported previously by Kamper, Lea & Lustig 1957. Measurements have also been made on the excited level of the ground 2 P multiplet of 19 F. They yield: a ½ = 10244.21 ± 0.03 Mc/s, g J ( J = ½) = 0.66561 ± 0.00003. An analysis of the magnetic hyperfine constants in the ground multiplets of 17 O and 19 F shows that in neither case do they yield consistent values for the two parameters < r -3 > and | ψ (0)| 2 usually associated with magnetic hyperfine structure. All measurements of hyperfine structure in these multiplets are consistent, however, with the requirements of LS coupling theory which introduce a third parameter into the magnetic hyperfine operator. The discrepancy is attributed to polarization effects, other than spin polarization of the core s electrons, brought about by the exchange interaction between electrons.

Solvent Effect on Rotational Relaxation Time of Ammonium Ion

“…The magnetic relaxation of the 2 D nucleus ( I = 1) is caused by the so-called quadrupole interaction, i.e., the interaction between the electric quadrupole moment of the nucleus and the electric field gradient at the nucleus. , The deuteron spin-lattice relaxation time, T 1 (D), at the extreme narrowing limit is then expressed by 21,22 where eQ , eq , and α represent the quadrupole moment of the 2 D nucleus ( Q = −2.73 × 10 -27 cm 2 ), the main axis component of the electric field gradient (efg) at the 2 D nucleus, and the asymmetry parameter, respectively. τ c is the correlation time of the fluctuation of the field gradient.…”

Solvent Effect on Rotational Motion of Perchlorate Ion

“…The rotational relaxation times of the perchlorate ion in various solvents were determined by the spin−lattice relaxation times of the 17 O nucleus of the perchlorate ions. The magnetic relaxation of 17 O ( I = 5/2) is caused by a so-called quadrupole interaction; that is, the interaction between the electric quadrupole moment of the nucleus and the electric field gradient at the nucleus. , The 17 O spin−lattice relaxation time, T 1 , at the extreme narrowing limit is then expressed by eq 1: 19 where eQ , eq , and α represent the quadrupole moment of the 17 O nucleus ( Q = −0.0265 × 10 -24 cm 2 ), the main axis component of the electric field gradient (efg) at the 17 O nucleus, and the asymmetry parameter, respectively, and τ c is the correlation time of the fluctuation of the field gradient. In the present case, the τ c value corresponds to the rotational relaxation time of the perchlorate ion associated with the second rank spherical harmonics, τ 2r . , …”

Absence of Static Loop-Current Magnetism at the Apical Oxygen Site inHgBa2CuO4+δfrom NMR

“…The ratio can be estimated as A cp /A p = (10/4)κ where κ is an empirical constant. For atomic fluorine (the same electronic configuration as O − ), κ = −0.1 [36], giving a ratio of A cp /A p = 0.25. This would place an upper bound on A p corresponding to at most a 40% contribution to ∆K ax , suggesting that the majority of its contribution comes from a dipolar field such as a magnetic moment on the Cu site.…”