Femtosecond
SI unit of time
A femtosecond is one billionth of one millionth, or one quadrillionth of a second. It can be written as 10-15 second. Even shorter than this is an attosecond.
- 200 femtoseconds - the fastest chemical reactions
- 300 femtoseconds - how long it takes for the atoms of an iodine molecule to vibrate
