Basic Principles of Magnetic Resonance

Abstract

The spinning charged particle having an angular momentum quantum number of 1/2 was introduced in Chap. 4 to illustrate the quantum-mechanical nature of spectroscopic transitions. This system is particularly suitable for such a purpose because the component of the transition dipole moment in any direction in space can be made an eigenvalue property by choosing an appropriate state. In Chap. 1 it was noted that the ideas presented in this book were historically first discovered and applied in the study of such systems. For these reasons, and because of the remarkable simplicity of the quantum-mechanical calculations in this case, the first detailed application of material developed in the first five chapters will be made to quantum transitions of spin−1/2 particles in a magnetic field (magnetic resonance spectroscopy). Chapter 4 was devoted to magnetic resonance in molecular beams, so that the quantum systems could be studied one at a time. By way of contrast, in this chapter the emphasis will be placed on spin−1/2 particles in bulk samples, and the statistical methods introduced in Chap. 5 must be employed.