I Goikoetxea

Publications (2)6.12 Total impact

• Article: Dissociative and non-dissociative adsorption dynamics of N2 on Fe(110).

  I Goikoetxea, M Alducin, R Díez Muiño, J I Juaristi
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  ABSTRACT: We study the adsorption dynamics of N(2) on the Fe(110) surface. Classical molecular dynamics calculations are performed on top of a six-dimensional potential energy surface calculated within density functional theory. Our results show that N(2) dissociation on this surface is a highly activated process that takes place along a very narrow reaction path with an energy barrier of around 1.1 eV, which explains the measured low reactivity of this system. By incorporating energy exchange with the lattice in the dynamics, we also study the non-dissociative molecular adsorption process. From the analysis of the potential energy surface, we observe the presence of two distinct N(2) adsorption wells. Our dynamics calculations show that the relative population of these adsorption sites varies with the incident energy of the molecule and the surface temperature. We find an activation energy of around 150 meV that prevents molecular adsorption under thermal and hypothermal N(2) gas exposure of the surface. This finding is also consistent with the available experimental information.
  Physical Chemistry Chemical Physics 04/2012; 14(20):7471-80. · 3.57 Impact Factor
• Source

  Available from: Ricardo Diez Muino

  Article: Dissipative effects in the dynamics of N(2) on tungsten surfaces.

  I Goikoetxea, J I Juaristi, M Alducin, R Díez Muiño
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  ABSTRACT: The role of electron-hole pair excitations in the dynamics of N(2) on W(100) and W(110) is evaluated using a theoretical model that accounts for the six-dimensionality of the problem in the whole calculation. The six-dimensional potential energy surface is determined in each case from an extensive grid of energies calculated with density functional theory. Dissipative effects due to electron-hole pair excitations are introduced in the classical dynamics equations through a friction force. Corresponding electron friction coefficients are calculated for each atom in the molecule with density functional theory in a local density approximation. Our results show that electronic friction plays a very minor role in the dissociative dynamics of N(2) in both tungsten faces. A similar conclusion is reached when we calculate the energy lost by the reflecting molecules.
  Journal of Physics Condensed Matter 07/2009; 21(26):264007. · 2.55 Impact Factor