A Global Full-Dimensional Potential Energy Surface for the K₂Rb₂ Complex and Its Lifetime

Area of Science:

• Physical Chemistry
• Computational Chemistry
• Chemical Dynamics

Background:

• Understanding the reaction KRb + KRb → K₂ + Rb₂ is crucial for chemical dynamics.
• Accurate potential energy surfaces (PES) are essential for simulating reaction pathways and kinetics.

Purpose of the Study:

• To develop a full-dimensional global potential energy surface for the KRb + KRb reaction.
• To accurately represent ab initio data and enable reliable dynamical calculations.

Main Methods:

• Calculated 20,759 ab initio points using coupled cluster singles, doubles, and perturbative triples (CCSD(T)) method.
• Extrapolated calculations to the complete basis set limit.
• Represented the PES using the permutation-invariant polynomial-neural network method for high fidelity.

Main Results:

• Developed a high-fidelity global potential energy surface with a root-mean-square error of 1.86 cm^-1.
• Identified key topographical features of the PES, including minima and saddle points.
• Estimated the Rice-Ramsperger-Kassel-Marcus lifetime of the K₂Rb₂ intermediate as 227 ns.

Conclusions:

• The developed PES accurately models the KRb + KRb reaction.
• The calculated intermediate lifetime shows good agreement with experimental data.
• This work provides a valuable tool for further theoretical and experimental investigations of this reaction system.