N-Mode Quantized Anharmonic Vibronic Hamiltonians for Matrix Product State Dynamics

TL;DR

This paper introduces a new n-mode quantized framework for modeling anharmonic vibronic Hamiltonians, enabling precise quantum dynamics simulations of complex photochemical processes using matrix product states.

Contribution

The authors develop a second-quantized n-mode vibronic Hamiltonian framework integrated with DMRG for accurate high-dimensional quantum dynamics calculations.

Findings

Demonstrated accurate excited state quantum dynamics of maleimide.

Analyzed convergence and parameter choices for the DMRG algorithm.

Validated the approach's reliability for complex photochemical systems.

Abstract

Theoretical predictions of photochemical processes are essential for interpreting and understanding spectral features. Reliable quantum dynamics calculations of vibronic systems require precise modeling of anharmonic effects in the potential energy surfaces and off-diagonal nonadiabatic coupling terms. In this work, we present the n-mode quantization of all vibronic Hamiltonian terms comprised of general high-dimensional model representations. This results in a second-quantized framework for accurate vibronic calculations employing the density matrix renormalization group algorithm. We demonstrate the accuracy and reliability of this approach by calculating the excited state quantum dynamics of maleimide. We analyze convergence and the choice of parameters of the underlying time-dependent density matrix renormalization group algorithm for the n-mode vibronic Hamiltonian, demonstrating that it enables accurate calculations of complex photochemical dynamics.