Universal Steps in Quantum Dynamics with Time-Dependent Potential-Energy Surfaces: Beyond the Born-Oppenheimer Picture

Abstract

In the conditional approach to molecular dynamics the electron-nuclear wavefunction is exactly decomposed into an ensemble of nuclear wavepackets governed by conditional time-dependent potential-energy surfaces (\(\mathbb{C}\)-TDPESs) [G. Albareda, et al., Phys. Rev. Lett. 105, 123002 (2014)]. Employing a one-dimensional model system we show that for strong nonadiabatic couplings the \(\mathbb{C}\)-TDPESs exhibit steps that bridge between piecewise adiabatic shapes. By a detailed analysis of the steps, we discuss the ultimate nature of electron-nuclear correlations and by comparing them with the discontinuities of the exact time-dependent potential-energy surface of the exact factorization approach we elaborate on the universality of this feature when a single time-dependent potential-energy surface governs the nonadiabatic nuclear dynamics.