Equbal Asif, Leavesley Alisa, Jain Sheetal Kumar, Han Songi
Department of Chemistry and Biochemistry , University of California, Santa Barbara , Santa Barbara , California 93106 , United States.
Department of Chemical Engineering , University of California, Santa Barbara , Santa Barbara , California 93106 , United States.
J Phys Chem Lett. 2019 Feb 7;10(3):548-558. doi: 10.1021/acs.jpclett.8b02834. Epub 2019 Jan 23.
The scope of this Perspective is to analytically describe NMR hyperpolarization by the three-spin cross effect (CE) dynamic nuclear polarization (DNP) using an effective Hamiltonian concept. We apply, for the first time, the bimodal operator-based Floquet theory in the Zeeman-interaction frame for two and three coupled spins to derive the known interaction Hamiltonian for CE-DNP. With a unified understanding of CE-DNP, and supported by empirical observation of the state of electron spin polarization under the given experimental conditions, we explain diverse manifestations of CE from oversaturation, enhanced hyperpolarization by broad-band saturation, to nuclear spin depolarization under magic-angle spinning.
本综述的范围是使用有效哈密顿量概念，通过三自旋交叉效应（CE）动态核极化（DNP）来分析描述核磁共振超极化。我们首次在塞曼相互作用框架中，将基于双峰算符的弗洛凯理论应用于两个和三个耦合自旋，以推导CE-DNP的已知相互作用哈密顿量。基于对CE-DNP的统一理解，并在给定实验条件下电子自旋极化状态的经验观察支持下，我们解释了CE的多种表现形式，从过饱和、宽带饱和增强超极化到魔角旋转下的核自旋去极化。
