论文标题
设计静态固体中的宽带脉冲动态核极化序列
Designing broadband pulsed dynamic nuclear polarization sequences in static solids
论文作者
论文摘要
动态核极化（DNP）是一种NMR超极化技术，可通过微波炉（MW）辐射介导从高极化的未配对电子到NMR活性核的极化转移。使用任意波形发电机生成任意形状的MW脉冲的能力为明显提高DNP的鲁棒性和多功能性的机会在许多方面都类似于脉冲NMR的早期阶段。我们在这里介绍了基于单旋矢量有效的哈密顿理论的新型设计原理，以开发新的宽带DNP脉冲序列，即绝热的XIX-DNP实验和宽带振幅调制信号增强（基础）实验。我们证明，绝热的基本脉冲序列可以达到$ \ sim $ 360的DNP $^{1} $ h增强系数，这一记录以$ 0.35 t和80 k的静态固体效果优于所有先前已知的脉冲DNP序列。基本DNP实验的带宽约为$^{1} $ h larmor频率（$ \ sim $ 50 MHz）的3倍。
Dynamic nuclear polarization (DNP) is an NMR hyperpolarization technique that mediates polarization transfer from highly polarized unpaired electrons to NMR-active nuclei via microwave (mw) irradiation. The ability to generate arbitrarily shaped mw pulses using arbitrary waveform generators opens up the opportunity to remarkably improve the robustness and versatility of DNP, in many ways resembling the early stages of pulsed NMR. We present here novel design principles based on single-spin vector effective Hamiltonian theory to develop new broadband DNP pulse sequences, namely an adiabatic XiX-DNP experiment and a broadband amplitude modulated signal enhanced (BASE) experiment. We demonstrate that the adiabatic BASE pulse sequence may achieve a DNP $^{1}$H enhancement factor of $\sim$ 360, a record that outperforms all previously known pulsed DNP sequences at $\sim$ 0.35 T and 80 K in static solids. The bandwidth of the BASE-DNP experiments is about 3 times the $^{1}$H Larmor frequency ($\sim$50 MHz).
