A NEW THEORY OF NMR FOR EXTENDED OBJECTS. Nuclear magnetic resonance (NMR) isn't just an imaging technique, but a valuable spectroscopic tool for deducing the chemical environment and structural layout of atoms in different environments. This is because the NMR spectrum of an atom (or to be more precise, the spectrum of the atom's nuclear magnetic states) is different depending on the local geometry, just as an atom's allowed electron energies will be different if the atom is suddenly lodged in a crystal with many other atoms. Previous NMR theories have been able to explain accurately what the NMR spectrum ought to be only for atoms or atom clusters in isolation. Now, physicists at UC Berkeley (Steven Louie, louie@jungle.berkeley.edu, 510-642-1709) have devised a method which for the first time makes possible rigorous calculations of the NMR spectra of extended systems such as crystals, surfaces, polymers, or even amorphous materials; given the coordinates of the atoms, the Berkeley researchers were able to predict the spectrum. They tried out their theory on an industrially important material---synthetic diamond films used, for example, as coatings for tools and engine parts. The prediction of the NMR spectrum for carbon atoms in the diamond films was in close agreement with the observed spectrum. (Francesco Mauri et al., Physical Review Letters, 22 Sept. 1997.)