Page 336 - Academic Press Encyclopedia of Physical Science and Technology 3rd Analytical Chemistry

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Encyclopedia of Physical Science and Technology EN010C-493 July 19, 2001 20:30

Nuclear Magnetic Resonance

(NMR)

Bernard C. Gerstein

Iowa State University

I. Introduction
II. The Nucleus as a Probe of Molecular Structure;
Internal Interactions and the Effects of Motion
III. NMR Spectra of Liquids
IV. NMR in Solids
V. Pulse and Fourier Transform NMR
VI. Two-Dimensional NMR
VII. Multiple Quantum NMR
VIII. Medical Imaging

GLOSSARY MHz Millions of cycles per second.
Quadrupole Ellipsoidal electric charge distribution.
Anisotropic Nonuniform in space; not spherically sym-
metric.
Chemical shift Shift in NMR frequency due to local THE PHENOMENON of nuclei absorbing resonant ra-
nuclear chemical environment as compared to a ref- dio frequency energy in a static magnetic field is called
erence frequency. nuclear magnetic resonance (NMR). This phenomenon is
Dipolar coupling Interaction between two nuclei behav- always accompanied by nuclear relaxation. Nuclear mag-
ing as classical magnets. netic resonance spectroscopy is routinely used to deter-
Isotropic Uniform in all directions in space; spherically mine structures of molecules in liquids and in organic
symmetric. molecular solids. The applications of NMR spectroscopy
Isotropic value One third of the sum of the diagonal are diverse. In medicine, NMR spectroscopy is used to
elements of a 3 × 3 matrix representing an ellipsoidal evaluate the extent of damage to heart muscles of patients
surface. who have suffered severe coronary infraction. The chemist
kHz Thousand of cycles per second (cps). can use it to examine coal to determine the presence of

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