Understanding spin dynamics

Experimental methods employing spin resonance effects (nuclear magnetic resonance and electron spin resonance) are broadly used in molecular science due to their unique potential to reveal mechanisms of molecular motion, structure, and interactions. The developed techniques bring together biologists investigating dynamics of proteins, material science researchers looking for better electrolytes, or nanotechnology scientists inquiring into dynamics of nano-objects. Nevertheless, one can profit from the rich source of information provided by spin resonance methods only when appropriate theoretical models are available. The obtained experimental results reflect intertwined quantum-mechanical and dynamical properties of molecular systems, and to interpret them one has to first understand the quantum-mechanical principles of the underlying process. This book concentrates on the theory of spin resonance phenomena and the relaxation theory, which have been discussed from first principles to introduce the reader to the language of quantum mechanics used to describe the behaviour of atomic nuclei and electrons. There is a long way from knowing complex formulae to apply them correctly to describe the studied system. The book shows through examples how symbols can be "replaced" in equations by using properties of real systems in order to formulate descriptions that link the quantities observed in spin resonance experiments with dynamics and structure of molecules. -- from back cover Content: Preface Classical description of spin resonance Larmor precession and Bloch equations Introduction to spin relaxation The nature of relaxation processes Correlation functions and spectral densities The simplest relaxation formula Bi-exponential relaxation Formal theory of spin relaxation The concept of density operator The Liouville von Neumann equation and relaxation rates Liouville space and Redfield kite Validity range of the perturbation theory Spin relaxation in time domain Spin resonance lineshape analysis The concept of spin resonance spectrum Spin resonance spectrum and motion Examples of spin resonance spectra Rigid spectra and the lineshape theory Spin resonance spectra and correlation functions Spin relaxation - a more general approach Generalized spectral densities Residual dipolar interactions Interference effects Cross-correlation effects Hierarchy of spin relaxation processes Electron spin resonances of spins 1/2 ESR spectra and scalar interactions for 15N systems ESR spectra and scalar interactions for 14N systems ESR spectra at low frequencies g - tensor anisotropy Nuclear spin relaxation in paramagnetic liquids Proton relaxation and hyperfine coupling Translational dynamics in paramagnetic liquids Effects of electron spin relaxation Hilbert space and spin relaxation Spin resonance beyond perturbation range Intermediate spin resonance spectra Stochastic Liouville formalism 2H NMR spectroscopy and motional heterogeneity 2H NMR spectroscopy and mechanism of motion Deviations from perturbation approach Dipolar relaxation and quadrupolar interactions Quadrupole relaxation enhancement (QRE) Perturbation approach to Quadrupole Relaxation Enhancement Polarization transfer QRE and internal dynamics of molecules Effects of mutual spin interactions ESR spectra for interacting paramagnetic centres Interference effects for nitroxide radicals Spin interactions and molecular geometry Dynamic Nuclear Polarization Principles of Dynamic Nuclear Polarization (DNP) DNP and ESR Spectrum Anisotropic and Internal Dynamics Anisotropic rotation Internal dynamics Index Annotation Experimental methods employing spin resonance effects (nuclear magnetic resonance and electron spin resonance) are broadly used in molecular science due to their unique potential to reveal mechanisms of molecular motion, structure, and interactions. The developed techniques bring together biologists investigating dynamics of proteins, material science researchers looking for better electrolytes, or nanotechnology scientists inquiring into dynamics of nano-objects. Nevertheless, one can profit from the rich source of information provided by spin resonance methods only when appropriate theoretical models are available. The obtained experimental results reflect intertwined quantum mechanical and dynamical properties of molecular systems, and to interpret them one has to first understand the quantum mechanical principles of the underlying processes. This book concentrates on the theory of spin resonance phenomena and the relaxation theory, which have been discussed from first principles to introduce the reader to the language of quantum mechanics used to describe the behaviour of atomic nuclei and electrons. There is a long way from knowing complex formulae to apply them correctly to describe the studied system. The book shows through examples how symbols can be "replaced" in equations by using properties of real systems to formulate descriptions that link the quantities observed in spin resonance experiments with dynamics and structure of molecules." 1. Classical description of spin resonance -- 2. Introduction to spin relaxation -- 3. Formal theory of spin relaxation -- 4. Spin resonance lineshape analysis -- 5. Spin relaxation : a more general approach -- 6. Electron spin resonance of spins 1/2 -- 7. Nuclear spin relaxation in paramagnetic liquids -- 8. Spin resonance beyond perturbation range -- 9. Dipolar relaxation and quadrupolar interactions -- 10. Effects of mutual spin interactions -- 11. Dynamic nuclear polarization -- 12. Anisotropic and internal dynamics