Nuclear Quadrupole Relaxation of Nitrogen in Hydrazine

Abstract

Six resonance lines due to two non-equivalent positions for each N 14 nucleus in addition to the nonaxial symmetry of the crystalline field gradient which gives rise to three resonance transitions, \(E_{0}{\ooalign{\)\leftharpoonup\(\crcr\)\rightharpoondown\(}}E_{+}\), \(E_{0}{\ooalign{\)\leftharpoonup\(\crcr\)\rightharpoondown\(}}E_{-}\) and \(E_{-}{\ooalign{\)\leftharpoonup\(\crcr\)\rightharpoondown\(}}E_{+}\), were observed, and the experiments of saturation recovery were carried out for these lines at liquid nitrogen temperature. The observed frequencies are 4.611 MHz, 2.617 MHz and 1.994 MHz for the system I and 4.567 MHz, 2.670 MHz and 1.890 MHz for the system II at 77°K. Observed recovery of the intensity of the resonance lines after pumping was found to be expressible as the sum of two exponential terms. The transition probabilities of the thermal spinlattice relaxation between the two of the above three transitions were determined. The observed time constants of the relaxation, T 1 s and T 1 l , and the transition probabilities, W Δ , W - , and W + , corresponding to \(E_{-}{\ooalign{\)\leftharpoonup\(\crcr\)\rightharpoondown\(}}E_{+}\), \(E_{0}{\ooalign{\)\leftharpoonup\(\crcr\)\rightharpoondown\(}}E_{-}\) and \(E_{0}{\ooalign{\)\leftharpoonup\(\crcr\)\rightharpoondown}} E + are as follows: For the system I ; T 1 s =1.4±0.1 and T 1 l =3.6±0.1 (min). W Δ =0.091±0.030, W - =0.221±0.030 and W + =0.516±0.030 (×10 -1 sec -1 ). For the system II ; T 1 s =1.3±0.1 and T 1 l =3.8±0.1 (min). W Δ =0.110±0.030, W - =0.193±0.030 and W + =0.557±0.030 (×10 -1 sec -1 ). Pumping experiment clarified that the cross interactions exist between two different spin systems.