Molecular dissociation in the presence of catalysts: interpreting bond breaking as a Quantum Dynamical Phase Transition

ANDRÉS RUDERMAN; AXEL D. DENTE; ELIZABETH SANTOS; HORACIO M. PASTAWSKI

JOURNAL OF PHYSICS CONDENSED MATTER

IOP PUBLISHING LTD

Lugar: Londres; Año: 2015 vol. 27 p. 315501 - 315501

0953-8984

In this work we show that molecular chemical bond formation and dissociation in the presenceof the d-band of a metal catalyst can be described as a quantum dynamical phase transition(QDPT). This agrees with DFT calculations that predict sudden jumps in some observables asthe molecule breaks. According to our model this phenomenon emerges because the catalystprovides for a non-Hermitian Hamiltonian. We show that when the molecule approachesthe surface, as occurs in the Heyrovsky reaction of H2, the bonding H2 orbital has a smoothcrossover into a bonding molecular orbital built with the closest H orbital and the surfacemetal d-states. The same occurs for the antibonding state. Meanwhile, two resonancesappear within the continuous spectrum of the d-band, which are associated with bonding andantibonding orbitals between the furthest H atom and the d-states at the second metallic layer.These move toward the band center, where they collapse into a pure metallic resonance and analmost isolated H orbital. This phenomenon constitutes a striking example of the non-trivialphysics enabled when one deals with non-Hermitian Hamiltonian beyond the usual wide bandapproximation.Keywords: atoms, molecule, transition