Halo-substituted azobenzenes adsorbed at Ag(111) and Au(111) interfaces: Structures and optical properties

Abstract

The adsorption of azobenzene (AB), ortho fluoro-azobenzene (FAB) and ortho chlor-azobenzol (ClAB), in both the cis and trans isomers, at the Au(111) and Ag(111) surfaces is investigated using plane wave density functional (PW-DFT) calculations with the revPBE-vdW-DF functional. The resulting adsorption energies and internal structures of AB adsorbed to both metal surfaces are in broad agreement with available experimental data. In the gas phase, FAB and ClAB feature a significant reduction in the energy difference between the two isomeric states, compared with AB. This relative reduction in the energy difference is still significant for the adsorbed form of FAB but is only weakly apparent for ClAB. The absorption spectra of the molecules have also been calculated, with the halogen substituents generating significant changes in the gas phase, but only a modest difference for the adsorbed molecules.

Distinct Differences in Peptide Adsorption on Palladium and Gold: Introducing a Polarizable Model for Pd(111)

“…k -point meshes of 4 × 4 × 1 and 6 × 8 × 1 were used for the geometry optimizations and single-point calculations, respectively. These cutoffs (and the convergence criteria) are consistent with those previously used to determine the adsorption energies of a wide range of molecules to the Au(111) and Ag(111) surfaces. ,, …”

“…These cutoffs (and the convergence criteria) are consistent with those previously used to determine the adsorption energies of a wide range of molecules to the Au(111) and Ag(111) surfaces. 16,18,57 The Pd(111) interface was constructed from a p(4 × 3), p(4 × 4), or p(6 × 3) supercell, depending on the size of the adsorbate (Table S1 cases, the palladium slab was four atomic layers thick. All systems had periodic boundary conditions applied in all three dimensions and were constructed such that along the z axis (perpendicular to the slab plane), a distance of at least 10 Å separated the molecule from the periodic image of the slab surface.…”

“…These DFT calculations were performed using the revPBE-vdW-DF functional, , which uses an explicit nonlocal correlation term to approximately capture contributions to the dispersion interaction. The adsorption energies of molecules to the Au(111) and Ag(111) interfaces obtained using the revPBE-vdW-DF functional were found to be reasonably consistent with reported experimental data. ,− However, to ensure that the DFT data used to parametrize the PdP-CHARMM FF are reasonable, here we have tested a number of different dispersion-inclusive functionals and compared our findings for each functional with each other and existing experimental data. The PdP-CHARMM FF was then parametrized against the data obtained from the functional that provided the best overall agreement with experimental data.…”

Adsorption and rotational barrier for a single azobenzene molecule on Au(111) surface*

“…This value gives a reasonable accuracy as compared with the experimental value of 2.97 ± 0.05 Å and the calculated value of 3.5 Å using the revPBE-vdW-DF functional. [37] Finally, the rotational barrier of an azobenzene molecule anchored at the kink site is obtained by examining the rotational energy potential as a function of molecular orientation. With the adsorption height fixed at 3.25 Å, the rotational energy potential curves are obtained by single-point calculations with the PBE-D3 approach.…”