Institute of Mathematics, Physics and Mechanics, Jadranska 19, 1000 Ljubljana, Slovenia.
J Magn Reson. 2011 Sep;212(1):149-53. doi: 10.1016/j.jmr.2011.06.023. Epub 2011 Jul 1.
The use of Zeeman perturbed 14N nuclear quadrupole resonance (NQR) to determine the ν+ and ν-14N lines in polycrystalline samples with several nonequivalent nitrogen atoms was investigated. The 14N NQR line shift due to a weak external Zeeman magnetic field was calculated, assuming isotropic distribution of EFG tensor directions. We calculated the broad line distribution of the ν+ and ν- line shifts and experimentally confirmed the calculated Zeeman field dependence of singularities (NQR peaks) in cyclotrimethylenetrinitramine (RDX) and aminotetrazole monohydrate (ATMH). The calculated and measured frequency shifts agreed well. The proposed measurement method enabled determination of which 14N NQR lines in ATMH belong to ν+ and which to ν- transitions.
利用塞曼扰动的 14N 核四极共振（NQR）来确定具有几个不等效氮原子的多晶样品中的 ν+和 ν-14N 线。在外加弱磁场作用下，NQR 线位移可以通过假设 EFG 张量方向的各向同性分布来计算。我们计算了 ν+和 ν-线位移的宽线分布，并通过实验证实了在环三亚甲基三硝胺（RDX）和氨基四唑一水合物（ATMH）中奇异点（NQR 峰）的计算磁场依赖性。计算和测量的频率位移吻合较好。所提出的测量方法能够确定 ATMH 中的哪些 14N NQR 线属于 ν+跃迁，哪些属于 ν-跃迁。
