INVESTIGADORES
FUHR Javier Daniel
artículos
Título:
Interplay between Hydrogen Bonding and MoleculeSubstrate Interactions in the Case of Terephthalic Acid Molecules on Cu(001) Surfaces
Autor/es:
J. D. FUHR; A. CARRERA; N. MURILLO-QUIRÓS; L. J. CRISTINA; A. COSSARO; A. VERDINI; L. FLOREANO; J. E. GAYONE; H. ASCOLANI
Revista:
JOURNAL OF PHYSICAL CHEMISTRY C
Editorial:
AMER CHEMICAL SOC
Referencias:
Lugar: Washington; Año: 2012 vol. 117 p. 1287 - 1296
ISSN:
1932-7447
Resumen:
The adsorption and self-assembling properties of terephthalic acid (TPA)
molecules deposited on Cu(001) at room temperature have been
systematically studied with both experimental and theoretical tools. The
system forms two phases at room temperature: the metastable β-phase and
the stable (3 × 3) one. In the case of the β phase, low-energy electron
diffraction and scanning tunneling microscopy (STM) results indicate
that it has a (9√2 × 2√2) R45° unit cell with exactly the same
molecular coverage as the (3 × 3) phase. In addition, the
high-resolution X-ray photoelectron-spectroscopy spectra of the O 1s
core level indicate that the irreversible β → (3 × 3) transition
involves the following two processes: (i) deprotonation of the complete
carboxyl groups remaining in the metastable phase and (ii) eventual
rearrangement of the molecules into the 3 × 3 configuration. We explored
possible molecular configurations for the β phase with different degree
of deprotonation (including structures with Cu adatoms) by means of
density functional theory calculations. Our theoretical results indicate
the formation of strong bonds between the O atoms in carboxylates and
the Cu atoms of the surface, which causes a bending of the molecules and
a buckling of the first Cu layer. In the (3 × 3) phases, we show that
the bending produces observable effects in the molecular STM images.
Moreover, the strong interaction between the carboxylates and the Cu
atoms at the step edges drives the reorientation of the surface steps
along the 100 crystallographic directions.