The retro-ene reaction of gaseous immonium ions revisited

The retro-ene reaction is a common reaction of metastable immonium ions, leading to the expulsion of an alkene molecule. The kinetic energy release that accompanies this reaction decreases with alkyl substitution on the γ-carbon of the immonium ion. A number of authors have taken this result to indicate that the retro-ene reaction proceeds in a non-concerted manner via a carbocation intermediate. Using ab initio calculations to test this hypothesis we find that the retro-ene reaction is a concerted process, in which the reactant immonium ion is connected to the products via a single six-membered cyclic transition state. The calculated energy barriers and the measured kinetic energy releases are highly sensitive to alkyl substitution at the γ-position, which indicates that a substantial fraction of the positive charge of the transition state resides at the γ-carbon, not that the retro-ene reaction is a stepwise process with a carbocation intermediate

Energy Spectrum of a constrained Quantum Particle and the Willmore Energy of the constraining Surface

Geometric and topological bounds are obtained for the first energy level gap of a particle constrained to move on a compact surface in 3-space. Moreover, geometric properties are found which allows for stationary and uniformly distributed wave functions to exist on the surface

A distributed-object infrastructure for corporate websites

A corporate website is the virtual representation of a cor-poration or organization on the Internet. Corporate web-sites face numerous problems due to their large size and complexity, and the nonscalability of the underlying Web infrastructure. Current solutions to these problems gener-ally rely on traditional scaling techniques such as caching and replication. These are usually too restrictive, however; taking a one-size-fits-all approach and applying the same solution to every document. We propose Globe as a founda-tion upon which to build scalable corporate websites, and introduce GlobeDoc, a website model based on Globe dis-tributed shared objects. This paper describes GlobeDoc, highlighting the design and technical details of the infras-tructure. 1