A Fourier transform infrared reflection absorption spectroscopy study of chemisorbed PF3 on Ni(111): Coverage and temperature dependence

Publisher Website
Google Scholar
Abstract
The P–F symmetric stretch fundamental mode of PF3 chemisorbed on the Ni(111) surface has been measured with Fourier transform infrared reflection absorption spectroscopy. Strong adsorbate–adsorbate interactions lead to a net increase in frequency from 858 cm−1 at the lowest coverage to 916 cm−1 at the highest coverage. At 273 K the band shape is symmetric with a FWHM of 6 cm−1 at both low and high coverages indicating a uniform environment for PF3 molecules in both coverage limits. At intermediate coverages the band is broad and asymmetric with unresolved components indicating a wide distribution of intermolecular distances on the surface. The low coverage frequency is 40 cm−1 lower than in the Ni(PF3)4 complex indicating interactions between the F atoms of PF3 and nearest‐neighbor Ni atoms on the Ni(111) surface. This interaction is reduced as higher lying torsional states of chemisorbed PF3 become thermally populated, leading to a strong temperature dependence of the P–F stretch band shape at low coverages.