Understanding NMR Spectroscopy

This text is aimed at people who have some familiarity with high-resolution NMR and who wish to deepen their understanding of how NMR experiments actually 'work'. This revised and updated edition takes the same approach as the highly-acclaimed first edition. The text concentrates on the description of commonly-used experiments and explains in detail the theory behind how such experiments work. The quantum mechanical tools needed to analyse pulse sequences are introduced set by step, but the approach is relatively informal with the emphasis on obtaining a good understanding of how the experiments actually work. The use of two-colour printing and a new larger format improves the readability of the text. In addition, a number of new topics have been introduced: * How product operators can be extended to describe experiments in AX2 and AX3 spin systems, thus making it possible to discuss the important APT, INEPT and DEPT experiments often used in carbon-13 NMR. * Spin system analysis i.e. how shifts and couplings can be extracted from strongly-coupled (second-order) spectra. * How the presence of chemically equivalent spins leads to spectral features which are somewhat unusual and possibly misleading, even at high magnetic fields. * A discussion of chemical exchange effects has been introduced in order to help with the explanation of transverse relaxation. * The doublequantum spectroscopy of a threespin system is now considered in more detail. Reviews of the First Edition "For anyone wishing to know what really goes on in their NMR experiments, I would highly recommend this book" - Chemistry World ".I warmly recommend for budding NMR spectroscopists, or others who wish to deepen their understanding of elementary NMR theory or theoretical tools" - Magnetic Resonance in Chemistry

InhaltsangabePreface. Preface to the first edition. 1 What this book is about and who should read it. 1.1 How this book is organized. 1.2 Scope and limitations. 1.3 Context and further reading. 1.4 Online resources. 1.5 Abbreviations and acronyms. 2 Setting the scene. 2.1 NMR frequencies and chemical shifts. 2.2 Linewidths, lineshapes and integrals. 2.3 Scalar coupling. 2.4 The basic NMR experiment. 2.5 Frequency, oscillations and rotations. 2.6 Photons. 2.7 Further reading. 2.8 Exercises. 3 Energy levels and NMR spectra. 3.1 The problem with the energy level approach. 3.2 Introducing quantum mechanics. 3.3 The spectrum from one spin. 3.4 Writing the Hamiltonian in frequency units. 3.5 The energy levels for two coupled spins. 3.6 The spectrum from two coupled spins. 3.7 Three spins. 3.8 Summary. 3.9 Further reading. 3.10 Exercises. 4 The vector model. 4.1 The bulk magnetization. 4.2 Larmor precession. 4.3 Detection. 4.4 Pulses. 4.5 Onresonance pulses. 4.6 Detection in the rotating frame. 4.7 The basic pulse-acquire experiment. 4.8 Pulse calibration. 4.9 The spin echo. 4.10 Pulses of different phases. 4.11 Offresonance effects and soft pulses. 4.12 Further reading. 4.13 Exercises. 5 Fourier transformation and data processing. 5.1 How the Fourier transform works. 5.2 Representing the FID. 5.3 Lineshapes and phase. 5.4 Manipulating the FID and the spectrum. 5.5 Zero filling. 5.6 Truncation. 5.7 Further reading. 5.8 Exercises. 6 The quantum mechanics of one spin. 6.1 Introduction. 6.2 Superposition states. 6.3 Some quantum mechanical tools. 6.4 Computing the bulk magnetization. 6.5 Time evolution. 6.6 RF pulses. 6.7 Making faster progress: the density operator. 6.8 Coherence. 6.9 Further reading. 6.10 Exercises. 7 Product operators. 7.1 Operators for one spin. 7.2 Analysis of pulse sequences for a one-spin system. 7.3 Speeding things up. 7.4 Operators for two spins. 7.5 Inphase and antiphase terms. 7.6 Hamiltonians for two spins. 7.7 Notation for heteronuclear spin systems. 7.8 Spin echoes and J-modulation. 7.9 Coherence transfer. 7.10 The INEPT experiment. 7.11 Selective COSY. 7.12 Coherence order and multiple-quantum coherences. 7.13 Summary. 7.14 Further reading. 7.15 Exercises. 8 Twodimensional NMR. 8.1 The general scheme for two-dimensional NMR. 8.2 Modulation and lineshapes. 8.3 COSY. 8.4 DQF COSY. 8.5 Doublequantum spectroscopy. 8.6 Heteronuclear correlation spectra. 8.7 HSQC. 8.8 HMQC. 8.9 Longrange correlation: HMBC. 8.10 HETCOR. 8.11 TOCSY. 8.12 Frequency discrimination and lineshapes. 8.13 Further reading. 8.14 Exercises. 9 Relaxation and the NOE. 9.1 The origin of relaxation. 9.2 Relaxation mechanisms. 9.3 Describing random motion - the correlation time. 9.4 Populations. 9.5 Longitudinal relaxation behaviour of isolated spins. 9.6 Longitudinal dipolar relaxation of two spins. 9.7 The NOE. 9.8 Transverse relaxation. 9.9 Homogeneous and inhomogeneous broadening. 9.10 Relaxation due to chemical shift anisotropy. 9.11 Cross correlation. 9.12 Further reading. 9.13 Exercises. 10 Advanced topics in two-dimensional NMR. 10.1 Product operators for three spins. 10.2 COSY for three spins. 10.3 Reduced multiplets in COSY spectra. 10.4 Polarization operators. 10.5 ZCOSY. 10.6 HMBC. 10.7 Sensitivity-enhanced experiments. 10.8 Constant time experiments. 10.9 TROSY. 10.10 Doublequantum spectroscopy of a threespin system. 10.11 Further reading. 10.12 Exercises. 11 Coherence selection: phase cycling and field gradient pulses. 11.1 Coherence order. 11.2 Coherence transfer pathways. 11.3 Frequency discrimination and lineshapes. 11.4 The receiver phase. 11.5 Introducing phas

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