Ab initio Quantum and ab initio Molecular Dynamics of the Dissociative Adsorption of Hydrogen on Pd(100)

The dissociative adsorption of hydrogen on Pd(100) has been studied by ab initio quantum dynamics and ab initio molecular dynamics calculations. Treating all hydrogen degrees of freedom as dynamical coordinates implies a high dimensionality and requires statistical averages over thousands of trajectories. An efficient and accurate treatment of such extensive statistics is achieved in two steps: In a first step we evaluate the ab initio potential energy surface (PES) and determine an analytical representation. Then, in an independent second step dynamical calculations are performed on the analytical representation of the PES. Thus the dissociation dynamics is investigated without any crucial assumption except for the Born-Oppenheimer approximation which is anyhow employed when density-functional theory calculations are performed. The ab initio molecular dynamics is compared to detailed quantum dynamical calculations on exactly the same ab initio PES. The occurence of quantum oscillations in the sticking probability as a function of kinetic energy is addressed. They turn out to be very sensitive to the symmetry of the initial conditions. At low kinetic energies sticking is dominated by the steering effect which is illustrated using classical trajectories. The steering effects depends on the kinetic energy, but not on the mass of the molecules. Zero-point effects lead to strong differences between quantum and classical calculations of the sticking probability. The dependence of the sticking probability on the angle of incidence is analysed; it is found to be in good agreement with experimental data. The results show that the determination of the potential energy surface combined with high-dimensional dynamical calculations, in which all relevant degrees of freedon are taken into account, leads to a detailed understanding of the dissociation dynamics of hydrogen at a transition metal surface.Comment: 15 pages, 9 figures, subm. to Phys. Rev.

Making business-to-business international internet marketing effective: A study of critical factors using a case study approach

NoThe recent phenomenal growth in business activities dependent on the Internet has demonstrated that various potential advantages could be derived from using information and communication technology platforms. The Internet has enabled firms to reach out to global markets and has provided them with the opportunity to customize their strategies and offerings in an unprecedented way. These recent developments provide an exciting opportunity for research to study the dynamics involved in international Internet marketing (IIM) and, in particular, to examine closely the factors that could influence success in using this new technology for IIM activities. Using a business-to-business context and a multiple-case-study approach, this article focuses on two main areas of study: (1) the critical examination of the literature and identification of the most important factors that have a significant influence on business-to-business IIM and (2) the first-hand verification of how the identified factors are implemented in various organizational contexts