Vibrational predissociation dynamics of Cl2(B)-He2: a wave packet study

Area of Science:

• Physical Chemistry
• Quantum Dynamics
• Spectroscopy

Background:

• Vibrational predissociation is a key energy relaxation pathway in van der Waals complexes.
• Accurate theoretical modeling is crucial for understanding dissociation dynamics and product state distributions.
• Previous studies often faced challenges in achieving converged results due to computational limitations.

Purpose of the Study:

• To investigate the convergence of observable properties in Cl(2)(B)-He(2) vibrational predissociation.
• To assess the impact of grid size and propagation time on lifetimes and product distributions.
• To develop a practical model for estimating vibrational populations in related complexes.

Main Methods:

• Full dimensional wave packet propagation method employed.
• Systematic variation of grid size and propagation time in dissociative coordinates.
• Development and validation of an approximate model for vibrational population estimation.

Main Results:

• Predissociation lifetimes and Cl(2)(B) rotational distributions show good convergence with increased computational parameters.
• Cl(2) vibrational distributions exhibit very slow convergence, rendering grid size extrapolation impractical.
• The proposed approximate model yields realistic vibrational population distributions, consistent with experimental data.

Conclusions:

• Computational convergence of vibrational distributions in Cl(2)(B)-He(2) is challenging and requires careful consideration of dissociation artifacts.
• The developed approximate model provides a computationally efficient and accurate method for predicting vibrational populations.
• The model's simplicity and applicability extend to other BC(B)-Rg(2) complexes, aiding future research in van der Waals dynamics.