Evidence for a bound HeH2 halo molecule by diffraction from a transmission grating

Area of Science:

• Physical Chemistry
• Atomic and Molecular Physics
• Chemical Physics

Background:

• Van der Waals complexes are crucial for understanding intermolecular forces.
• Previous studies have explored similar weakly bound systems.
• The Helium-Hydrogen (HeH2) complex presents a unique system for studying fundamental interactions.

Purpose of the Study:

• To identify and characterize the HeH2 van der Waals complex.
• To investigate the properties of weakly bound complexes formed in a molecular beam.
• To demonstrate a novel method for detecting such complexes.

Main Methods:

• Production of a molecular beam via cryogenic free jet expansion of H2 in 4He.
• Detection of HeH2 complexes using first-order diffraction through a 100 nm transmission grating.
• Analysis of diffraction patterns with electron impact mass spectrometry to confirm complex identity.

Main Results:

• Successful identification of the HeH2 van der Waals complex.
• Characterization of the complex's behavior in a molecular beam.
• Discrimination against interfering ion fragments using mass spectrometry.

Conclusions:

• The HeH2 van der Waals complex can be effectively produced and identified using cryogenic free jet expansion and diffraction techniques.
• This method provides a sensitive approach for studying weakly bound molecular systems.
• The findings contribute to the understanding of interatomic forces in simple molecular complexes.