Quantum tunneling dynamical behaviour on weakly bound complexes: the case of a CO

Area of Science:

• Quantum Mechanics
• Chemical Physics
• Molecular Dynamics

Background:

• Quantum tunneling is a fundamental quantum mechanical phenomenon.
• The dynamics of quantum tunneling are strongly influenced by potential energy surface shapes.
• The carbon dioxide-nitrogen (CO2-N2) van der Waals complex exhibits spectral and dynamical features not explained by standard models.

Purpose of the Study:

• To investigate the quantum tunneling dynamics of the CO2-N2 van der Waals complex.
• To fully consider nuclear motions and nuclear spins in the treatment of CO2-N2 dynamics.
• To elucidate unexplained aspects of CO2-N2 quantum tunneling observed 85 years ago.

Main Methods:

• A first-principles treatment was employed to model the CO2-N2 van der Waals complex.
• Nuclear motions and nuclear spins were fully incorporated into the theoretical framework.
• Analysis focused on spectral and dynamical features arising from quantum tunneling.

Main Results:

• The CO2-N2 dimer displays complex spectral and dynamical characteristics.
• Quantum tunneling dynamics in CO2-N2 were explained, resolving long-standing mysteries.
• Evidence of vibrational memory and quantum localization effects was found.
• The CO2-N2 system serves as a prototype for studying tunneling-induced degeneracy lifting and large amplitude motions.

Conclusions:

• The study provides a comprehensive understanding of quantum tunneling in the CO2-N2 van der Waals complex.
• Findings offer insights into complex quantum effects in molecules with multiple potential wells, such as isomerization and tautomerism.
• The research clarifies previously unexplained quantum phenomena in molecular systems.