Eur. Phys. J. B (2018) 91: 139
https://doi.org/10.1140/epjb/e2018-90144-3

Regular Article

Nuclear quantum effects in electronic (non)adiabatic dynamics^★

¹ Laboratoire de Chimie Physique, UMR 8000 CNRS/University Paris-Sud, 91405 Orsay, France
² IBM Research GmbH, Zürich Research Laboratory, 8803 Rüschlikon, Switzerland
³ Institute for Applied Computing “Mauro Picone” (IAC), CNR, Via dei Taurini 19, 00185 Roma, Italy
⁴ School of Physics, University College of Dublin UCD – Belfield, Dublin 4, Ireland
⁵ Università di Roma La Sapienza, P.le A. Moro 5, 00185 Roma, Italy

^a e-mail: federica.agostini@u-psud.fr

Received: 8 March 2018
Received in final form: 4 May 2018
Published online: 2 July 2018

Abstract

Trajectory-based approaches to excited-state, nonadiabatic dynamics are promising simulation techniques to describe the response of complex molecular systems upon photo-excitation. They provide an approximate description of the coupled quantum dynamics of electrons and nuclei trying to access systems of growing complexity. The central question in the design of those approximations is a proper accounting of the coupling electron-nuclei and of the quantum features of the problem. In this paper, we approach the problem in the framework of the exact factorization of the electron-nuclear wavefunction, re-deriving and improving the coupled-trajectory mixed quantum-classical (CT-MQC) algorithm recently developed to solve the exact-factorization equations. In particular, a procedure to include quantum nuclear effects in CT-MQC is derived, and tested on a model system in different regimes.