Rapid Survey of Nuclear Quadrupole Resonance by Broadband Excitation with Comb Modulation and Dual-Mode Acquisition
Rapid Survey of Nuclear Quadrupole Resonance by Broadband Excitation with Comb Modulation and Dual-Mode Acquisition
复制标题
通过梳状调制和双模式采集宽带激励快速测量核四极共振
DOI：
10.1039/d0cp05309k
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
and K. Takeda
中科院分区：
文献类型：
--
作者：
Y. Hibe;Y. Noda;K. Takegoshi;and K. Takeda
核四极共振（NQR）提供了携带自旋量子数为1bbbb1 /2的原子核周围电场梯度信息的光谱，并为表征化学材料的电子结构提供了有用的线索。NQR的一个主要挑战是寻找迄今为止未知的共振频率，这些频率可能会在很宽的范围内分散，需要耗时的重复测量，并逐步增加频率。在这里，我们报告了一种高效的两步NQR协议，将快速扫描和频率梳结合在一起。在第一步中，宽带激励和同步信号采集，都是通过梳状调制的非绝热扫频双曲割线（HS）脉冲实现的，为在所研究的频率区域内共振的存在/不存在提供了线索。当且仅当检测到共振的符号时，实施第二步以补偿第一步的有限检测带宽并明确地确定NQR频率。我们还通过数值模拟研究了梳状调制HS脉冲下的自旋动力学，并通过实验验证了该方案的可行性，该方案被称为双模操作（RASGADO） NQR。
Nuclear Quadrupole Resonance (NQR) provides spectra carrying information as to the electric-field gradient around nuclei with a spin quantum number I > 1/2 and offers helpful clues toward characterizing the electronic structure of materials of chemical interest. A major challenge in NQR is finding hitherto unknown resonance frequencies, which can scatter over a wide range, requiring time consuming repetitive measurements with stepwise frequency increments. Here, we report on an efficient, two-step NQR protocol by bringing rapid-scan and frequency-comb together. In the first step, wideband excitation and simultaneous signal acquisition, both realized by a non-adiabatic, frequency-swept hyperbolic secant (HS) pulse with comb modulation, offers a clue for the existence/absence of the resonance within the frequency region under investigation. When and only when the sign of the resonance has been detected, the second step is implemented to compensate the limited detection bandwidth of the first and to unambiguously determine the NQR frequency. We also study the spin dynamics under the comb-modulated HS pulse by numerical simulations, and experimentally demonstrate the feasibility of the proposed scheme, which is referred to as RApid-Scan with GApped excitation with Dual-mode Operation (RASGADO) NQR.