Coexistence of Atomic and Molecular Chemisorption States: <span class="aps-inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow><mi>/</mi><mi>Pd</mi></math></span>(210)

Pia K. Schmidt; Klaus Christmann; Georg Kresse; Jürgen Hafner; Markus Lischka; Axel Groß

doi:10.1103/PhysRevLett.87.096103

Coexistence of Atomic and Molecular Chemisorption States: $H_{2} / Pd$ (210)

Pia K. Schmidt, Klaus Christmann, Georg Kresse, Jürgen Hafner, Markus Lischka, and Axel Groß

Phys. Rev. Lett. 87, 096103 – Published 10 August 2001

Abstract

A novel $H_{2}$ molecular adsorption state on metal surfaces has been detected by temperature-programmed desorption and electron energy loss spectroscopy experiments of the $H_{2} / Pd$ (210) system. The molecular nature of this state has been verified by isotope exchange experiments. This molecular state leads to a decrease of the surface work function while atomic hydrogen on Pd(210) causes an increase. Ab initio total-energy calculations have confirmed all experimental findings. Through these calculations the microscopic nature of this novel molecular adsorption state could be identified; it turns out that this state is stabilized by the presence of atomic hydrogen on the Pd(210) surface.