Oriented Polar Molecules Trapped in Cold Helium Nanodropets: Electrostatic Deflection, Size Separation, and Charge...

Area of Science:

• Atomic and Molecular Physics
• Nanoscale Science

Background:

• Helium nanodroplets (HeNDs) are weakly interacting quantum systems used as cold,’” inert pick-up gas for studying various species.
• Controlling and characterizing the size and properties of HeNDs is crucial for their application in spectroscopy and materials science.

Purpose of the Study:

• To develop and demonstrate a broadly applicable electrostatic deflection technique for studying helium nanodroplets doped with polar molecules.
• To enable size-dependent measurements and filtering of neutral nanodroplets.

Main Methods:

• Utilizing electrostatic fields to deflect helium nanodroplets doped with polar molecules.
• Analyzing droplet deflections to determine droplet size distributions.
• Implementing spatial filtering of the deflected beam for size selection.

Main Results:

• Achieved subkelvin temperatures and near-full orientation of polyatomic molecules within HeNDs.
• Demonstrated deflection of massive neutral systems (tens of thousands of atoms).
• Extracted droplet size distributions and measured dopant ionization probability as a function of droplet radius.
• Determined the mean free path for charge hopping through the helium matrix.

Conclusions:

• Electrostatic deflection is a powerful and broadly applicable method for characterizing and manipulating helium nanodroplets.
• The technique allows for size filtering of neutral nanodroplets, enabling size-dependent studies.
• Future applications include separation of doped and neat nanodroplets and advanced spectroscopic investigations.