Multidimensional Tunneling Dynamics Employing Quantum-Trajectory Guided Adaptable Gaussian Bases.

Area of Science:

• Computational Quantum Chemistry
• Theoretical Molecular Dynamics
• Chemical Physics

Background:

• Accurate representation of time-dependent wavefunctions is crucial for studying high-dimensional molecular systems.
• Standard methods face exponential scaling challenges for fully coupled anharmonic systems.
• Adaptable basis sets, like time-dependent Gaussians, offer a practical solution for managing complexity.

Purpose of the Study:

• To generalize the quantum-trajectory guided adaptable Gaussian (QTAG) bases method.
• To incorporate correlated (non-factorizable) basis functions into the QTAG framework.
• To assess the performance of the generalized QTAG method on benchmark tunneling models.

Main Methods:

• Generalization of the QTAG method to include correlated basis functions.
• Application to system/bath tunneling models with up to 20 dimensions.
• Analysis of dynamics using initial conditions simulating reactant/product well tunneling.

Main Results:

• The generalized QTAG method demonstrates high efficiency in capturing dominant dynamic features.
• A minimal 'semiclassical' description of bath modes is effective when combined with multi-Gaussian tunneling mode representation.
• The approach successfully models complex tunneling dynamics in multi-dimensional systems.

Conclusions:

• The generalized QTAG method provides an efficient and accurate approach for theoretical studies of molecular dynamics.
• This method significantly reduces computational complexity for high-dimensional anharmonic systems.
• The findings pave the way for more sophisticated simulations of quantum phenomena in complex molecular systems.