自旋动力学第八章 核自旋哈密顿量课件.pptVIP

第八章 核自旋的哈密顿量;8 Nuclear Spin Hamiltonian;8 Nuclear Spin Hamiltonian;Nuclear Spin Hamiltonian;8.2 Electromagnetic Interactions;8.2.1 Electric spin Hamiltonian;?(r);电场强度的梯度;氢原子的轨道：;8.2.1 Electric spin Hamiltonian;电四极矩：核;四极相互作用 与作用于核处的电场梯度密切相关 （核周围电荷分布） ;8.2.2 磁性的自旋相互作用Magnetic spin interactions;8.4 External Magnetic Fields;8.4.2 Radio-frequency field;8.4.3 梯度磁场 Gradient field;8.4.4 External spin interactions: summary;8.5 Internal Spin Hamiltonian;3. Direct dipole–dipole couplings: 直接磁相互作用 of nuclear spins with each other;5. Spin–rotation interactions： the interactions of the nuclear spins with magnetic fields generated by rotational motion of the molecules:;哄剧轧掸犬氰亮码帅的晕磅董铂侨扫束超茵千拐轰策拆钩沁基甸趟请铡贸自旋动力学第八章 核自旋哈密顿量课件自旋动力学第八章 核自旋哈密顿量课件;8.5.2 Simplification of the internal Hamiltonian;例1. 对易绝断近似（一级近似）;Secular Approximation;？;(ii) the rapid molecular motion in liquids and gases, and in some solids;8.6 Motional Averaging;各向同性无规转动：;2. In an anisotropic liquid: there is considerable molecular motion, but all orientations are not equally Probable ---- liquid crystal;8.6.3 Molecular translations;8.6.4 Intramolecular and intermolecular spin interactions;long-range and short-range intermolecular interactions: Short-range: interacting molecules share the same diffusion sphere. Long-range :Interacting molecules do not share the same diffusion sphere ;8.6.5 Summary of motional averaging;3. In an anisotropic liquid, Rotation partially averages all intramolecular spin interactions---anisotropic values. Diffusion completely averages short-range intermolecular interactions--- zero long-range intermolecular interactions survive;5. In certain molecular solids---- plastic crystals Unusual situation : fixed centres of gravity of the molecules with respect to the cry