Development and Characterization of a Narrow-Pulsed Molecular Beam System

A narrow-pulsed and velocity-controlled molecular beam system is constructed by using a high-speed chopper and a tempera-ture adjustable pulsed valve.The duration of the hydrogen molecular beam pulse is reduced to approximately 6.3μs and char-acterized using resonance-enhanced multi-photon ionization(REMPI)at a distance of～193 mm downstream from the nozzle.To precisely determine the velocity of the hydrogen molecules,a pump-probe tech-nique combining stimulated Raman pumping and REMPI is employed at a fixed distance(193 mm)with nanosecond lasers.By adjusting the temperature of the pulsed valve,the velocity of the hydrogen beam varies continuously from 1290 m/s to 3550 m/s.The sys-tem exhibits potential for multiple applications in the field of chemical reaction dynamics,including its potential to integrate with ion traps and surface scattering experiments.