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Updated: Jul 4, 2026
12:11
Computation of Atmospheric Concentrations of Molecular Clusters from ab initio Thermochemistry
Published on: April 8, 2020
Path integral Monte Carlo study of CO2 solvation in 4He clusters
Zheng Li1, Lecheng Wang, Hong Ran
1Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, China.
The Journal of Chemical Physics
|June 17, 2008
Summary
Helium-4 atoms surrounding carbon dioxide molecules form a donut structure around N=5 atoms. This structural change explains observed shifts in carbon dioxide
Area of Science:
- Quantum mechanics
- Chemical physics
- Condensed matter physics
Background:
- Understanding the behavior of small clusters is crucial for developing theories of larger systems.
- Helium clusters are weakly interacting systems that serve as excellent models for studying quantum effects.
Purpose of the Study:
- To investigate the structural and dynamical properties of helium-4 ((4)He) clusters doped with carbon dioxide (CO2).
- To elucidate the relationship between cluster size and observable spectroscopic properties.
Main Methods:
- Path Integral Monte Carlo (PIMC) simulations were employed to study (4)He(N)-CO2 clusters (N<=17) at finite temperatures.
- A high-level ab initio interaction potential (CCSD(T)) was used for He-CO2 interactions, accounting for CO2's asymmetric stretch.
Main Results:
- Calculated the shift in the CO2 antisymmetric stretching (nu3) band origin and effective rotational constant as a function of cluster size.
- Observed a turnaround in these spectroscopic properties around N=5 helium atoms.
- This turnaround correlates with a structural transition to a "donut" configuration.
Conclusions:
- The study successfully explains experimental observations of spectroscopic shifts in (4)He(N)-CO2 clusters.
- A distinct structural change, forming a donut shape with helium atoms in equatorial positions, occurs around N=5 and dictates the observed properties.
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