Selected configuration interaction with truncation energy error and application to the Ne atom

Selected configuration interaction (SCI) for atomic and molecular electronic structure calculations is reformulated in a general framework encompassing all CI methods. The linked cluster expansion is used as an intermediate device to approximate CI coefficients BK of disconnected configurations (those that can be expressed as products of combinations of singly and doubly excited ones) in terms of CI coefficients of lower-excited configurations where each K is a linear combination of configuration-state-functions (CSFs) over all degenerate elements of K. Disconnected configurations up to sextuply excited ones are selected by Brown's energy formula, ΔEK=(E-HKK)BK2/(1-BK2), with BK determined from coefficients of singly and doubly excited configurations. The truncation energy error from disconnected configurations, Δdis, is approximated by the sum of ΔEKS of all discarded Ks. The remaining (connected) configurations are selected by thresholds based on natural orbital concepts. Given a model CI space M, a usual upper bound ES is computed by CI in a selected space S, and EM=E S+ΔEdis+δE, where δE is a residual error which can be calculated by well-defined sensitivity analyses. An SCI calculation on Ne ground state featuring 1077 orbitals is presented. Convergence to within near spectroscopic accuracy (0.5 cm-1) is achieved in a model space M of 1.4× 109 CSFs (1.1 × 1012 determinants) containing up to quadruply excited CSFs. Accurate energy contributions of quintuples and sextuples in a model space of 6.5 × 1012 CSFs are obtained. The impact of SCI on various orbital methods is discussed. Since ΔEdis can readily be calculated for very large basis sets without the need of a CI calculation, it can be used to estimate the orbital basis incompleteness error. A method for precise and efficient evaluation of ES is taken up in a companion paper

Basis set superposition error effects, excited-state potential energy surface and photodynamics of thymine

En aquesta tesi he estudiat l'efecte de l'error de superposició de base (BSSE) en la planaritat d'algunes molècules. He observat que l'ús d'alguns mètodes de càlcul amb determinades funcions de base descriuen mínims d'energia no planars per les bases nitrogenades de l'ADN. He demostrat que aquests problemes es poden arreglar utilitzant el mètode Counterpoise per corregir el BSSE en els càlculs. En aquesta tesi també he estudiat la fotofísica de la timina i els resultats mostren que existeixen dos camins de relaxació des de l'estat excitat que permeten la regeneració de l'estructura inicial de forma ultraràpida.

The light representation of religion and power in sound

The thematic and anathematic in music-making a reflection occurring after listening to an art song and a pop song from the 19th and 20th century Levantine music. Bach’s Orchestral Suites keep popping up, elegantly unveiling “the truth”.

Memory and power : two movements

The institutions that work with the preservation and diffusion of cultural heritage - be them archive, libraries, museums, art galleries or cultural centres - present a certain discourse about reality. To understand this discourse, composed by sound and silence, by fullness and emptiness, by presence and absence, by remembrance and forgetting, an operation is implied, not only with the enunciation of speech and its gaps, but also the comprehension of that which causes to speak, of who is speaking and of the point whence one speaks. Preservation and destruction, or, in another way, conservation and loss, walk hand in hand in the arteries of life. As suggested by Nietzsche (1999, p.273), it is impossible to live without loss, it is entirely impossible to live avoiding destruction to play its game and drive the dynamics of life on. However, by means of a kind of tautological argument, one often justifies preservation by the imminence of loss and memory by the threat of forgetting. Thus, one ceases to consider that the game and the rules of the game between forgetting and memory are not fed by themselves and that preservation and destruction are not opposed in a deadly duel, but instead they complement one another and are always at the service of subjects that build themselves and are built through social practices. To indicate that memories and forgettings can be sown and cultivated corroborates the importance of working towards the denaturalisation of these concepts and towards the understanding that they result from a construction process also involving other forces, such as: power. Power is a sower, a promoter of memories and forgettings.

Potential energy surface and MULTIMODE vibrational analysis of C2H3+

A full dimensional, ab initio-based semiglobal potential energy surface for C2H3+ is reported. The ab initio electronic energies for this molecule are calculated using the spin-restricted, coupled cluster method restricted to single and double excitations with triples corrections [RCCSD(T)]. The RCCSD(T) method is used with the correlation-consistent polarized valence triple-zeta basis augmented with diffuse functions (aug-cc-pVTZ). The ab initio potential energy surface is represented by a many-body (cluster) expansion, each term of which uses functions that are fully invariant under permutations of like nuclei. The fitted potential energy surface is validated by comparing normal mode frequencies at the global minimum and secondary minimum with previous and new direct ab initio frequencies. The potential surface is used in vibrational analysis using the "single-reference" and "reaction-path" versions of the code MULTIMODE. (c) 2006 American Institute of Physics.

Application of integrated GPS and GIS technology for reducing construction waste and improving construction efficiency

This paper presents a study on applying an integrated Global Position System (GPS) and Geographacial Information System (GIS) technology to the reduction of construction waste. During the study, a prototype study is developed from automatic data capture system such as the barcoding system for construction material and equipment (M&E) management onsite, whilst the integrated GPS and GIS technology is combined to the M&E system based on the Wide Area Network (WAN). Then, a case study is conducted to demonstrate the deployment of the system. Experimental results indicate that the proposed system can minimize the amount of onsite material wastage.

Urbanisation and its impact on building energy consumption and efficiency in China

The People's Republic of China and its 1.3 billion people have experienced a rapid economic growth in the past two decades. China's urbanisation ratio rose from around 20% in the early 1980s to 45% in 2007 [China Urban Research Committee. Green building. Beijing: Chinese Construction Industrial Publish House; 2008. ISBN 978-7-112-09925-2.]. The large volume and rapid speed of building construction rarely have been seen in global development and cause substantial pressure on resources and the environment. Government policy makers and building professionals, including architects, building engineers, project managers and property developers, should play an important role in enhancing the planning, design, construction, operation and maintenance of the building energy efficiency process in forming the sustainable urban development. This paper addresses the emerging issues relating to building energy consumption and building energy efficiency due to the fast urbanisation development in China.