CHEM 214 Lecture Notes - Lecture 17: Magnetic Dipole, Gyromagnetic Ratio, Magnetic Moment

• School: McGill University
• Department: Chemistry
• Course: CHEM 214
• Professor: Anthony Mittermaier

Document Summary

Looking at nmr in a quantum mechanical point of view. Many nuclei have intrinsic angular momentum, nuclei behave like massive object that are spinning. There is a quantum number associated with spin angular momentum, s. nuclei with intrinsic angular momentum are the ones used in nmr spectroscopy. Nuclei with s > 0 (nuclei that have intrinsic angular momentum) also have magnetic dipole moments; they behave like bar magnets. The whole principle of nmr is based on the fact that the nuclei are placed in strong magnetic field. The magnetic dipole moment is parallel to nuclear spin angular momentum. If we know where spin angular momentum vector is pointing we also know where the north south magnetic momentum vector is, pointing in same direction. The constant of probability is called the gyromagnetic ratio, y (gamma). (magnetic dipole moment is given ). Magnetic dipole momentum is proportional to total angular momentum with this constant of proportionality gamma.