Imaginary time Gaussian dynamics of the Ar3 cluster

Area of Science:

• Computational Physics
• Quantum Chemistry
• Thermodynamics

Background:

• Semiclassical Gaussian approximations are crucial for analyzing low-temperature thermodynamic properties of atomic clusters.
• Existing thawed Gaussian methods are computationally expensive for these investigations.

Purpose of the Study:

• To introduce a computationally efficient frozen Gaussian approximation for the imaginary time propagator.
• To apply this method to study the dissociation of the argon trimer.
• To investigate the influence of artificial confinement on cluster thermodynamic properties.

Main Methods:

• Developed a frozen Gaussian approximation with a specialized width matrix for cluster dynamics.
• Applied the method to the argon trimer system.
• Analyzed thermodynamic properties including mean energy and specific heat.

Main Results:

• The frozen Gaussian method provides results comparable in quality to more expensive thawed Gaussian methods.
• Observed a distinct classical-like dissociation transition for the argon trimer at approximately 20K.
• Identified quantum effects influencing low-temperature behavior and a slight shift in transition temperature.

Conclusions:

• The developed frozen Gaussian approximation is a viable and efficient alternative for studying atomic cluster thermodynamics.
• Artificial confinement significantly impacts calculated thermodynamic properties, necessitating careful consideration in cluster studies.
• The study resolves the previously unobserved dissociation transition in argon trimers, offering new insights into cluster behavior.