Elucidating the structure and dynamics of CO ad-layers on MgO surfaces. Issue 48 (5th November 2019)

• Record Type: Journal Article
• Authors: Maul, Jefferson; Spoto, Giuseppe; Mino, Lorenzo; Erba, Alessandro
• Is Part Of: Physical chemistry chemical physics. Volume 21:Issue 48(2019)
• Page Start: 26279
• Page End: 26283
• Publication Date: 2019-11-05
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c9cp05418a
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The structure and dynamics of the ordered CO ad-layer on MgO surfaces is determined by combining theoretical quantum-mechanical calculations and experimental infrared spectroscopic measurements. Abstract : The combination of quantum-mechanical simulations and infrared absorption spectroscopy measurements provides a clear picture for a long standing puzzle in surface science: the actual structure and vibrational dynamics of the low-temperature ordered CO monolayer adsorbed on (001) MgO surfaces. The equilibrium structure of the commensurate (4 × 2) adsorbed phase consists of three CO molecules per primitive cell (surface coverage of 75%) located at two inequivalent sites: one molecule seats upright on top of a Mg site while two molecules, tilted off the normal to the surface, are symmetrically positioned relative to the upright one with anti-parallel projections on the surface. This configuration, long believed to be incompatible with measured polarization infrared spectra, is shown to reproduce all observed spectral features, including a new, unexpected one: the vanishing anharmonicity of CO stretching modes in the monolayer.