Small rare-gas clusters in soft x-ray pulses.

Area of Science:

• Atomic and molecular physics
• Plasma physics
• X-ray science

Background:

• Rare-gas clusters are studied for their unique properties under irradiation.
• Free electron lasers (FELs) provide intense, tunable soft x-ray sources.
• Understanding cluster-radiation interaction is crucial for various applications.

Purpose of the Study:

• To develop a microscopic model for rare-gas cluster interaction with soft x-ray radiation.
• To investigate the charging dynamics and charge state distributions within these clusters.
• To elucidate the mechanisms leading to high atomic charge states.

Main Methods:

• Development of a microscopic theoretical model.
• Simulation of rare-gas cluster interactions with free electron laser (FEL) soft x-ray radiation.
• Analysis of charge imbalances and atomic charge state evolution.

Main Results:

• The overall charging of rare-gas clusters is found to be relatively low.
• Unexpectedly high atomic charge states are observed within the clusters.
• Charge imbalances inside the cluster are identified as the primary cause.

Conclusions:

• High atomic charge states arise from internal charge redistribution, not just overall cluster ionization.
• Increased absorption via inverse bremsstrahlung, facilitated by high intermediate charge states, plays a key role.
• Non-uniform charge distribution within the cluster is critical for generating extreme charge states.