Ahmed Hassan Zewail (February 26, 1946 - August 2, 2016) was an Egyptian and American chemist, known as the "father of femtochemistry".

An attosecond (abbreviated as as) is a unit of time in the International System of Units (SI) equal to 10−18 or 1⁄1 000 000 000 000 000 000 (one quintillion) of a second.

Chemical reactions are the processes that result in the transformation of one or more chemical substances into different substances.

Femtochemistry is the area of physical chemistry that studies chemical reactions on extremely short timescales (approximately 10−15 seconds or one femtosecond, hence the name) in order to study the very act of atoms within molecules (reactants) rearranging themselves to form new molecules (products).

The International System of Units (SI) is a globally accepted and standardized system of measurement used in various fields such as science, engineering, and trade.

Iodine is a chemical element with the symbol I and atomic number 53.

Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum.

A micrometre, also known as a micrometer, is a unit of length in the metric system.