Strong Fano resonance of oxygen-hydrogen bonds on oblique angle deposited Mg nanoblades

Abstract

Magnesium hydroxide [Mg (OH)2] thin layers were formed by a chemical reaction between Mg nanoblades and water. Infrared (IR) spectroscopy showed a OH bond-stretching vibrational mode at 3699 cm-1. The assignment was verified by reactions with heavy water, producing OD bonds with the expected isotopic frequency shift. An asymmetric Fano line shape was observed for the OH layer on metallic Mg, while a symmetric Lorentzian (or Bright-Wigner) profile was observed for the OH layer on insulating Mg H2. The results indicate that the OH layer on the Mg nanoblades is so thin that the vibrational mode couples to the free-electron continuum of Mg metal. © 2008 American Institute of Physics.