Electron diffraction of 1,4-dichlorobenzene embedded in superfluid helium droplets

Area of Science:

• Physical Chemistry
• Materials Science
• Quantum Chemistry

Background:

• Superfluid helium droplets offer a unique environment for studying molecular cluster formation.
• Understanding cluster growth dynamics is crucial for various chemical and physical processes.

Purpose of the Study:

• To investigate the structural evolution of 1,4-dichlorobenzene (2ClB) clusters.
• To determine cluster concentrations and optimal structural models.
• To explore deviations from theoretical minimum energy structures during cluster formation.

Main Methods:

• Electron diffraction on 2ClB embedded in superfluid helium droplets.
• Multivariable linear regression for fitting cluster concentrations and structures.
• Density functional theory (DFT) and high-level quantum mechanical calculations.

Main Results:

• Cluster growth follows Poisson distribution statistics, with monomers and dimers being most abundant.
• 2ClB dimers exhibit a parallel structure with a specific rotational angle.
• Cluster structures (trimers and tetramers) deviate from global minimum energy configurations predicted by theory.
• Reduced interlayer distances in dimers improve experimental-theoretical agreement.

Conclusions:

• The structure evolution of 2ClB clusters is size-dependent and non-trivial.
• Deviations from theoretical minimum energy structures suggest the influence of rapid cooling in superfluid helium.
• This study provides insights into cluster formation dynamics in cryogenic environments.