Surface Chemistry and Interfacial Bonding of Benzyl Isocyanide on Cu(111)

Abstract

The adsorption, thermal chemistry and interfacial electronic structure of benzyl isocyanide (BzNC, C6H5CH2NC) dosed on Cu(111) at 160 K have been studied using temperature-programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and ultraviolet photoelectron spectroscopy (UPS). During TPD, BzNC dissociates above 280 K, leading to desorption of C6H5CH3, H2, and HCN. Intact BzNC also desorbs with local rate maxima at four different temperatures247, 285, 340, and 455 Kdenoted β1−β4. The major peak (β1, 455 K) is present for all doses. The other three β peaks grow in together and appear as β1 approaches saturation. The β2 peak at 247 K is very narrow and is attributed to BzNC desorption from crowded 2D islands accompanied by a stabilizing rearrangement of the remaining BzNC. Reflecting a strong permanent dipole that is oriented perpendicular to the surface, adsorption of 1 monolayer (ML) of BzNC on Cu(111) lowers the work function by 2.35 eV. The XPS and UPS results for this saturation coverage at...