5: Nuclear Magnetic Resonance (NMR) Spectroscopy - Introduction
- Page ID
- 398259
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- 5.1: Nuclear Spin and Magnetic Field
- In this Chapter, we will discuss why certain types of atomic nuclei are sensitive to the external magnetic field due to their quantum property known as the “spin”. We further will cover the dependence between the magnetic sensitivity of atomic nuclei and quantization of their energy levels once these atoms are exposed to the magnetic fields. You will be able to quantitatively determine the frequency of magnetic resonance of a specific type of atomic nucleus exposed to a magnetic filed.
- 5.2: Basic NMR Excite-Record Experiment and Related Spectrum
- In this Chapter, we will consider the most basic type of NMR experiment: acquiring a 1D data for a spin-½ sample pre-equilibrated in an external, static magnetic field. We will see how the properties of the NMR setup (e.g., static magnet power) and of the target system (e.g. the gyromagnetic ratio value) are affecting the obtained spectra. Finally, we will briefly explain why we are seeing spectra at all, that is why nuclei of the same chemical type report different NMR frequencies.
- 5.3: Chemical shift in units of Hz and ppm
- This Chapter introduces the other most common unit to measure and report the NMR resonance frequency: ppm, parts-per-million. We will consider examples when the frequency units of Hz (1/second) are the most justified choice and the opposite cases- when ppm’s should be used. We will also start describing quantitatively how raw NMR signal, S(t), depend on time t, initial current S0, and two properties of the target nucleus: resonance frequency Ω (or ν) and relaxation rate R.
- 5.4: Fourier Transformation (FT)- from an FID to a Spectrum
- This Chapter introduces the most generally applied method for conversion of raw NMR signal (FID) to NMR spectra- Fourier transformation (FT). Specifically, we will see how the key parameters of an FID introduced in the previous chapter affect the key properties of an NMR spectral resonance: position, intensity and linewidth.
- 5.5: Effects of the Sample, Equipment and Recording Regimes on the NMR Spectral Sensitivity and Resolution.
- This Chapter describes how key elements of NMR data collection (properties of sample molecules, their concentration, magnet strength B0, recording regimes) affect the two fundamental qualities of the recorded data: spectral resolution and spectral sensitivity.