ATOMIC PHYSICS

Author: CUCHÍ OTERINO JUAN CARLOS.
Year: 2004.
University: ZARAGOZA [www.unizar.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Author: BASANTA RAMOS MIGUEL ÁNGEL.
Year: 2005.
University: AUTÓNOMA DE MADRID [www.uam.es].
Place of defense: CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS, UNIVERSIDAD AUTÓNOMA DE MADRID.

Summary: The Functional Theory of Gravity has been of particular relevance in the past 40 years for the analysis of the structure and properties of systems, especially in those systems with a large number of atoms, as it offers the possibility of resolving the energy ground state through a Hamiltoniano cash one-electron. The result of this reduction is not possible to know the wave function of the exact problem, but it is known only energy and loads of the system. However, in dealing with the resolution of systems in which the interplay of type van der Waals by DFT, the various approximations of functional canje-correlación existing today are not satisfactory (LDA and EMG, mainly). The aim of this thesis has been to create a model based on DFT which takes into account the interaction of type van der Waals. It is important that this model is easily applicable to systems with a large number of atoms, and these are systems in which the interplay of van der Waals type is especially important (interaction enzima-sustrato, DNA chain, three-dimensional configuration protein interaction between graphite composite character ..). The thesis has been analyzed three different systems: on the one hand, and dimers of Helium Neon, and by another interaction between two surfaces Grafeno. There are models that DFT can describe quite well the first two, but there are few that can describe the interaction between two surfaces Grafeno, and sometimes with results that do not match well with the experimental data. This thesis presents a model based on DFT to solve the three systems mentioned above, and has a large degree of freedom and adaptability to be extrapolated to new systems. It is also a simple model for easy application to perform calculations on systems with a large number of atoms. To achieve this, it has used the theory DFT applied to a localized orbital base, and has described a new hamiltoniano one-electron cash with which to solve the equations Kohn-Sham, where the hoppoing has been replaced by a new hopping which includes an average of the interaction between type van der Waals. Thus, the calculation of the energy canje-correlación is easier.

Author: GARCÍA ALDEA DAVID.
Year: 2005.
University: NACIONAL DE EDUCACIÓN A DISTANCIA [www.uned.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: This thesis is part of the so-called Functional Formalismo of density, which allows a full description of an electronic system for the sole use dela electron density. More specifically, it focuses on the scheme known as "Orbital free" requiring explicit functional approximations to the kinetic energy. The main contributions of this thesis is on the one hand, the development of new functional kinetic not local, and on the other, present a quantitative procedure by which it is possible to easily measure the quality of the kinetic energy density. This procedure wants to raise to go beyond the study of the kinetic energy that each functional wins being tested locally in each functional point of space. The method has been applied on a total of 21 functional kinetic semilocales acting on the systems that are simple electronic densities of the top ten atoms of the periodic table. The finding surprised most important is the fact that correcciones.semilocales the functional Thomas-Fermi despite giving best total kinetic energies, worsen the properties of the local density of kinetic energy. Have been developed, likewise, three proposals functional whose most notable feature is that its non-local part is based on the mathematical structure of functional von Weizsà ¤ cker. These functional á la von Weizsà ¤ cker have proven to be suitable for use variational, as they have provided a good description in a minimization of the atom of helium, and in general have shown similar quality to that of the functional type Thomas-Fermi.

Author: BENGOECHEA APEZTEGUÍA JAIONE.
Year: 2005.
University: PAÍS VASCO [www.ehu.es].
Place of defense: FACULTAD DE CIENCIAS Y TECNOLOGÍA.

Summary: In memory of this thesis explores the possibility of using laser-produced plasmas as sources for spectroscopic measurement of parameters widening Stark. By emission spectroscopy, is the characterization of plasmas generated alloys Fe-Ni, determining distributions of temperature, density and density of atoms voters in the plasma. It draws optimal experimental conditions that provide plasmas more stable, more spherical symmetry. Investigation of autoabsorción of plasmas, with the aim of ensuring that lines measured optically with delegates. It describes him procedure for measuring constant widening Stark used as a reference line Fe I, whose constant widening is known. The pilot asymmetrical profile of this line is adjusted using a theoretical profile, which takes into account both in Stark broadening due to the electrons as due to the ions, which is responsible for asymmetry. Using a model based on the distribution parameter pasma, it is estimated the error of measuring parameters Stark due to inhomogeneidad feature of these sources. As an example of the experimental procedures developed in the thesis, it is determined the constant widening of a Stark line Fe I value very small and unknown, through a system with high spectral resolution.

Author: MANRIQUE ROSEL JAVIER.
Year: 2005.
University: COMPLUTENSE DE MADRID [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS FÍSICAS.
Place of preparation: FACULTAD DE CIENCIAS FÍSICAS (UCM), FACULTAD DE CIENCIAS EXPERIMENTALES Y TÉCNICAS (USP-CEU).

Summary: In this paper we have studied electronic transitions of various ions by spectroscopic techniques. There has been emission spectrum in the range 400-1700 A, which is produced in collisions slow ion beam Ni 10 + and Ni 9 + on He and Ar. Using this technique, known as spectroscopy based on the collision have been identified transitions and established energy levels Ni X. Besides these studies have been completed through spectroscopy of plasma produced by laser in the range spectral 140-400 A. Transitions Ni II in the interval spectral 2100-2600 A have been investigated in a pro laser produced plasma. It has made a study of the spatial distribution of plasma generated obtained distributions of electrons and temperatures that exist in the interior of the same. This would likely have obtained transition between the configurations 3d8 4p and 3d8 4s. The issuance of the visible spectrum of rare earth ions trapped in a network of CaF2 naturally has been registered during the heating of the sample after being bombarded with electrons accelerated to 10 NMeV. It has also been observed spectrum optically stimulated by a laser He-Ne. It has studied the kinetics which follows the emission thermoluminescent, gaining activation energy of the traps and identified transitions.

Author: Isla García Miguel.
Year: 2006.
University: VALLADOLID [www.uva.es].
Place of defense: Facultad de Ciencias.
Place of preparation: Facultad de Ciencias de la Universidad de Valladolid.

Summary: The line of inquiry over this thesis has focused on a realistic theoretical study of the dynamics of fragmented explosion Coulombiana of atomic aggregates. The main part has been based on the analysis of deuterium clusters that interact with a high-powered laser. The aim is to deepen and, as far as possible to try to play, the recent nuclear fusion experiments carried out with this technique (T. Ditmire et al., Nature 398, 489 (1999)), particularly in its early stages , the fastest and virtually inaccessible on a trial basis. Apart from that results are presented on the scattering of protons with clusters Li4. The method has been used for the simulation is the formalism of the Density Functional (DFT). Recent developments in the dynamic version of this formalism, ie the version of the time-dependent DFT (TD-DFT) allow study the response, both linear and non-linear, a little added to the atomic irradiation with a laser pulse duration of femtosegundos. Or with high-energy particles. The computer code that we used is the Octopus (MAL Marques A. Castro, GF Bertsch, A. Rubio, Computer Physics Communications, 151, 60 (2003)) recently developed by the group of Molecular Physics and Nanotechnology at the University of Valladolid in collaboration with other groups. Octopus combines (1) the calculation of the electronic excitation based on the explicit resolution of the equations of formalism TDDFT (equations Kohn and Sham time-dependent) and (2) a classical Molecular Dynamics to account for the movement of ions. In the first chapter of results of the thesis we have presented the results of computational simulations of fragmentation cluster D3 + (D2) 5 induced by an intense laser pulse and speed of 10 fs duration and intensities between 1012 and 1015 W/cm2. Analysis of the results reveals two different channels decay. In the first, the fragmentation process is relatively slow and occurs sequentially; pulse laser induced dissociation of trímero Central and, in a second step, is the movement of the fragments differentiated this trímero which induces destabilization and subsequent dissociation of molecular added. The second channel coupling is oberva for laser intensities of approximately twenty times higher than in the case of fragmentation slow. Here is what is a violent fragmentation of the cluster known as the explosion coulombiana. It suffers from the cluster ionization mass so that the nuclei stripped of their electrons are accelerated under the repulsive Coulomb forces and expelled from the system with very high kinetic energies. All this highlights the importance of the parameters of the laser in checking these processes so complicated to control and understand because of their nature as fast and high non-linearity and away from equilibrium. The influence of parameters such as frequency, intensity and polarization of the laser field have been analyzed. Proper choice of these parameters allows the observation of different output channels for trímero. When the field in a laser is tuned to different frequencies of resonance absorption spectrum, the parameter crucial difference is the kind of response the intensity. For low intensities which induces movements are electronic and vibrational excitation of the atomic nuclei. These atomic vibrations can increase or decrease the intensity of the electronic excitation. For high intensity laser, a process that occurs is an ionization followed by a subsequent explosion coulombiana. A mechanism of absorption multifotón highlighting is responsible for the ionization in these schemes are not linear. In addition, there are two possible routes to reach the blast coulombiana: through a swift and dire 8 cta ioni 451 sation and through a slower process recolisión electronics. When operating under conditions not resonant, requires higher laser intensities for answers similar to those that occur in the resonant cases. In conclusion, TDDFT is capable of dealing with highly non-linear processes, processes out of balance that will certainly have some very promising and interesting applications in the near future.