Semiclassical initial value representation for the quantum propagator in the Heisenberg interaction representation

Area of Science:

• Quantum Chemistry
• Computational Chemistry
• Theoretical Chemistry

Background:

• On-the-fly ab initio semiclassical time evolution is computationally expensive.
• Convergence of semiclassical calculations remains a significant challenge.

Purpose of the Study:

• To develop a computationally efficient semiclassical method for quantum dynamics.
• To improve convergence properties of semiclassical initial value representation (SCIVR) methods.

Main Methods:

• Formulation and numerical testing of a modified semiclassical interaction representation (SC-IR).
• Based on the wavefunction form of semiclassical propagation, simplifying implementation.
• Comparison with Herman-Kluk and Heller approximations using a 1D model system.

Main Results:

• The SC-IR method demonstrates improved convergence properties compared to standard SCIVR.
• The phase and prefactor in SC-IR vary more slowly, enhancing stability.
• The approach is shown to be simpler and cheaper to implement.

Conclusions:

• The modified SC-IR offers a viable and efficient approach for on-the-fly semiclassical simulations.
• This method facilitates the incorporation of force field information within semiclassical frameworks.
• The SC-IR method presents a promising alternative for accelerating quantum dynamics computations.