Effects of the air pressure on the wave-packet dynamics of gaseous iodine molecules at room temperature

Based on ultrafast laser pulses, time-resolved resonance enhancement coherent anti-Stokes Raman scattering (RE-CARS) is applied to investigate wave-packet dynamics in gaseous iodine. The effects of air pressure on the wave-packet dynamics of iodine molecules are studied at pressures ranging from 1.5 Torr to 750 Torr. The RE-CARS signals are recorded in a gas cell filled with a mixture of about 0.3 Torr iodine in air buffer gas at room temperature. The revivals and fractional revival structures in the wave-packet signal are found to gradually disappear with rising air pressure up to 750 Torr, and the decay behaviors of the excited B-state and ground X-state become faster with increasing air pressure, which is due to the collision effects of the molecules and the growing complexity of the spectra at high pressures.

► This study presents the wavepacket dynamics of iodine under different air pressures. ► Collision effects of the molecules on the wavepacket dynamics is investigated by the dramatic RE-CARS. ► The time-resolved tool vividly shows collision effects on the revivals and fractional revivals of the wavepacket.