A new Stark decelerator based surface scattering instrument for studying energy transfer at the gas-surface interface

Area of Science:

• Surface science
• Quantum mechanics
• Molecular beam epitaxy

Background:

• Surface scattering experiments are crucial for understanding surface chemistry and physics.
• Precisely controlling molecular quantum states and velocities is essential for detailed surface interaction studies.

Purpose of the Study:

• To design and characterize a novel apparatus for quantum-state resolved surface scattering experiments.
• To enable the preparation of quantum-state pure carbon monoxide (CO) molecule beams with tunable velocities.

Main Methods:

• Utilizing optical state-specific molecule preparation, a compact hexapole, and a Stark decelerator.
• Employing an ultrahigh vacuum surface scattering chamber with custom-built detectors, a variable-temperature sample mount (19-1337 K), and a Kelvin probe.
• Integrating a quadrupole mass spectrometer for high-resolution temperature programmed desorption (TPD) experiments.

Main Results:

• Successful preparation of carrier gas-free CO molecule pulses with controlled velocities (33-1000 m/s) and narrow distributions.
• Characterization of the apparatus's performance, including its ability to perform quantum-state resolved measurements.
• Demonstration of capabilities for surface cleaning, characterization, and adsorbate deposition.

Conclusions:

• The developed apparatus provides a powerful new tool for fundamental surface science research.
• Precise control over molecular beams opens new avenues for investigating surface reactions and dynamics.
• The system's versatility supports a wide range of surface scattering and adsorption studies.