Category: List of Bases 2006 Throughout the year RESEARCH IN CONDENSED MATTER PHYSICS

Title:

Joint ICTP/Democritos Informal Seminar on Chemical Physics "Lifting of IR {100} reconstruction by CO adsorption: An ab initio study"

Start Time:

11:00

Location:

ICTP (Main Building Lecture Room C)

Contact:

M. Poropat

Speaker(s):

P. GHOSH (Jawaharlal Nehru Centre, Bangalore)

Description:

The adsorption of CO on unreconstructed and reconstructed Ir{100} has been studied, using a combination of density functional theory and thermodynamics, to determine the relative stability of the two phases as a function of CO coverage, temperature and pressure. We obtain good agreement with experimental data. At zero temperature, the (1X5) reconstruction becomes less stable than the unreconstructed (1X1) surface when the CO coverage exceeds a critical value of 0.09 ML. The interaction between CO molecules is found to be repulsive on the reconstructed surface, but attractive on the unreconstructed, explaining the experimental observation of high CO coverage on growing (1X1) islands. At all temperatures and pressures, we find only two possible stable states: 0.05 ML CO c(2X2) overlayer on the (1X1) substrate, and the clean (1X5) reconstructed surface.