来自《耶鲁大学开放课程：新生有机化学 第7集 第7集》

• 
  
  In fact, the typical vibration amplitude,which depends on --
  而原子的振幅一般来说取决于
• 
  
  an atom that's off on the end of something is more floppy than one
  处在分子末端的原子比连结很多键的原子
• 
  
  that's held in by a lot of bonds in various directions,
  比如那些在笼里的原子
• 
  
  in a cage sort of thing
  要柔软的多
• 
  
  But typically they're vibrating by about 0.05 angstroms,
  但总的来说它们的振幅在约0.05埃
• 
  
  which is twenty-five times as big as the precision
  是所知的原子平均位置精度的
• 
  
  to which the position of the average is known.
  25倍
• 
  
  So no molecule looks like that at an instant,
  所以分子在任何一刻都不是静止的
• 
  
  the atoms are all displaced a little bit.
  分子都会发生一点位移
• 
  
  Now how big is that?
  这个移位有多大呢
• 
  
  Here, if you look at that yellow thing,
  看那个黄色的圆点
• 
  
  when it shrinks down, that's how big it is,
  如果收缩到底 就有这么大