Multidimensional Hydrogen Tunneling in Supported Molecular Switches: The Role of Surface Interactions

Abstract

The nuclear tunneling crossover temperature ($T_c$) of hydrogen transfer reactions in supported molecular-switch architectures can lie close to room temperature. This calls for the inclusion of nuclear quantum effects (NQE) in the calculation of reaction rates even at high temperatures. However, standard computations of NQE relying on parametrized dimensionality-reduced models, quickly become inadequate in these environments. In this letter, we study the paradigmatic molecular switch based on porphycene molecules adsorbed on metallic surfaces with full-dimensional calculations that combine density-functional theory for the electrons with the semi-classical ring-polymer instanton approximation for the nuclei. We show that the double intramolecular hydrogen transfer (DHT) rate can be enhanced by orders of magnitude due to surface fluctuations in the deep tunneling regime. We also explain the origin of an Arrhenius temperature-dependence of the rate below $T_c$ and why this dependence differs at different surfaces. We propose a simple model to rationalize the temperature dependence of DHT rates spanning diverse fcc [110] surfaces.

References in corpus (8)

• i-PI 2.0: A Universal Force Engine for Advanced Molecular Simulations
• i-PI: A Python interface for ab initio path integral molecular dynamics simulations
• Atom-Tunneling in Chemistry
• Density-functional model for van der Waals interactions: Unifying many-body atomic approaches with nonlocal functionals
• Tunnel splittings for one dimensional potential wells revisited
• Elucidating the NuclearQuantum Dynamics of Intramolecular Double Hydrogen Transfer in Porphycene
• Full- and reduced-dimensionality instanton calculations of the tunnelling splitting in the formic acid dimer
• Decisive role of nuclear quantum effects on surface mediated water dissociation at finite temperature

Cited by in corpus (4)

• i-PI 3.0: a flexible and efficient framework for advanced atomistic simulations
• Progress and Challenges in Ab Initio Simulations of Quantum Nuclei in Weakly Bonded Systems
• Dissipative Tunneling Rates through the Incorporation of First-Principles Electronic Friction in Instanton Rate Theory I: Theory
• Quantum rates in dissipative systems with spatially varying friction