Bonded Bells and Two-Dimensional Spectra [chapter]

Michaeleen Doucleff, Mary Hatcher-Skeers, Nicole J. Crane
2010 Pocket Guide to Biomolecular NMR  
Falling dominos. A bat hitting a baseball out of the stadium. A dog tugging on a leash. Energy transfer is all around us ( Fig. 2 .1). One of the most elegant demonstrations of energy transfer is "Newton's cradle" (Fig. 2. 2). You've probably seen this executive toy: five metal balls are attached to a metal frame by a thin wire, like five pendulums kissing each other. When the first ball is swung (Fig. 2.2a) , it hits the neighboring balls, but only the ball at the extreme end reacts and swings
more » ... d reacts and swings out (Fig. 2.2b) . The kinetic energy of the first ball is almost perfectly transmitted through the middle balls, causing only the ball at the end to move. Like the metal balls in "Newton's cradle," ringing atoms in molecules also transfer their excess energy to other atoms. NMR spectroscopists call this energy transfer coupling. This phenomenon is very useful for characterizing the details of molecular structures because it tells us which atoms are close to one another. We'll see how this works in the next two chapters. 19 M. Doucleff et al., Pocket Guide to Biomolecular NMR,
doi:10.1007/978-3-642-16251-0_2 fatcat:u5zyk5myunde3kbwijwyfik7om