Probing Laser-Induced Plasma Generation in Liquid Water

Area of Science:

• Physical Chemistry
• Chemical Physics
• Materials Science

Background:

• Understanding laser-water interactions is vital for fundamental science and applications.
• Tracking ultrafast atomistic movements after photoexcitation is challenging due to complexity.

Purpose of the Study:

• To explore the femtosecond evolution of liquid water under intense photoexcitation.
• To unveil microscopic details of ionic and electronic dynamics and energy transfer pathways.

Main Methods:

• Nonadiabatic quantum dynamics simulations were employed.
• Separate ionic and electronic dynamics were explicitly monitored at the atomic level.

Main Results:

• Liquid water exhibits a two-step heating process driven by strong-field effects and electronic excitations.
• Laser pulses cause molecular stretching, proton transfer, dissociation, and plasma generation.
• The resulting water plasma features free protons, nonequilibrium distributions, and metallic electronic states.

Conclusions:

• Intense laser irradiation induces complex ultrafast dynamics in liquid water.
• The study provides unprecedented microscopic insights into laser-excited water, including plasma formation.