A mathematical and computational review of Hartree-Fock SCF methods in Quantum Chemistry

We present here a review of the fundamental topics of Hartree-Fock theory in Quantum Chemistry. From the molecular Hamiltonian, using and discussing the Born-Oppenheimer approximation, we arrive to the Hartree and Hartree-Fock equations for the electronic problem. Special emphasis is placed in the most relevant mathematical aspects of the theoretical derivation of the final equations, as well as in the results regarding the existence and uniqueness of their solutions. All Hartree-Fock versions with different spin restrictions are systematically extracted from the general case, thus providing a unifying framework. Then, the discretization of the one-electron orbitals space is reviewed and the Roothaan-Hall formalism introduced. This leads to a exposition of the basic underlying concepts related to the construction and selection of Gaussian basis sets, focusing in algorithmic efficiency issues. Finally, we close the review with a section in which the most relevant modern developments (specially those related to the design of linear-scaling methods) are commented and linked to the issues discussed. The whole work is intentionally introductory and rather self-contained, so that it may be useful for non experts that aim to use quantum chemical methods in interdisciplinary applications. Moreover, much material that is found scattered in the literature has been put together here to facilitate comprehension and to serve as a handy reference.Comment: 64 pages, 3 figures, tMPH2e.cls style file, doublesp, mathbbol and subeqn package

Large landslides on passive continental margins: processes, hypotheses and outstanding questions

The volume, area affected, and runout of submarine landslides can exceed those of terrestrial events by two orders of magnitude. The Storegga Slide off Norway affected an area the size of Scotland and moved enough sediment to bury the entire country to a depth of 80 m. Modern geophysics provides a clear picture of large landslides and what their source and depositional areas look like. From this, we can deduce the processes that operated during downslope transport. However, our understanding of many aspects of landslide processes is based on hypotheses that are difficult to test. Elevated pore pressures are essential for landslide initiation on low continental margin slopes, yet understanding of how high pressures are generated or how fluid migration affects slope stability is limited. Sediments may be pre-conditioned for failure by the processes that originally deposited them, e.g., through creation of weak layers, but the processes and parameters that might control this are largely unknown. <br/

Governing social practice: technology and institutional change

In this article, we extend the concept of technology beyond the conventional understanding of systems and artifacts as embodiments of particular functionalities that are variously enacted in local settings. Technological artifacts or systems epitomize operational couplings that extend beyond the human-technology interface. Such couplings entail multiple, unobtrusive, back-staged links that evade human interpretation yet are critically involved in the reproduction and control of social relations. Cast in this light, technologies emerge as complex rationalized embodiments for structuring social relationships and, in this quality, complement and occasionally compete with institutional modes of governance. We explore these ideas in the empirical context of cultural memory organizations (e. g., libraries, archives, museums). As the outcome of the technological developments that have marked the field over the last two decades, the operations of memory institutions increasingly mingle with those of information aggregators and search engines. These developments reframe longstanding professional practices of memory organizations and, in this process, challenge their institutional mandate