Femtochemistry facts for kids

Femtochemistry is a special part of physical chemistry that looks at chemical reactions happening super fast. We're talking about incredibly short times, like one femtosecond. A femtosecond is one quadrillionth of a second (10⁻¹⁵ seconds)!

Imagine trying to watch a race where the runners move faster than light. Femtochemistry helps scientists see how atoms in molecules move and rearrange themselves. It's like taking a super-fast video of a chemical reaction as it happens.

A scientist named Ahmed Zewail first used the term "femtochemistry" in 1988. He showed that it's possible to watch atoms move during a reaction. He did this using very quick flashes of laser light. For his amazing work, Zewail won the Nobel Prize in Chemistry in 1999.

This field also helps us understand how important molecules like stem-loop RNA change their shapes. These changes are vital for how living things work.

How Scientists Study Fast Reactions

To study these super-fast reactions, scientists use a method called pump–probe spectroscopy. It's one of the most common ways to see what's happening.

The Pump and Probe Method

This method uses two or more quick flashes of light, like tiny laser pulses.

• The first pulse is called the pump pulse. It starts the chemical reaction. It might break a bond or give energy to a molecule.
• The second pulse is called the probe pulse. It checks on the reaction a very short time later.

Scientists change the time between the pump and probe pulses. By doing this, they can see how the reaction changes over time. It's like taking many snapshots at different moments of the reaction. This helps them build a full picture of the reaction's progress.

Examples of Femtochemistry

Femtochemistry has helped us understand many chemical processes. It shows us steps that we couldn't see before.

Bromine Dissociation

One example is studying how bromine molecules break apart. When a bromine molecule is hit by a special laser pulse (400 nm), its electrons quickly move onto individual atoms. This happens in just 140 femtoseconds! After 160 femtoseconds, the bromine atoms are already far apart.

See also

• Attosecond physics (even faster, 1 attosecond = 10⁻¹⁸ s)
• Femtotechnology
• Ultrafast laser spectroscopy
• Ultrashort pulse
• Flash photolysis