Application of photoluminescence and electroluminescence techniques to the characterization of intermediate band solar cells

The intermediatebandsolarcell (IBSC) is a photovoltaic device with a theoretical conversion efficiency limit of 63.2%. In recent years many attempts have been made to fabricate an intermediateband material which behaves as the theory states. One characteristic feature of an IBSC is its luminescence spectrum. In this work the temperature dependence of the photoluminescence (PL) and electroluminescence (EL) spectra of InAs/GaAs QD-IBSCs together with their reference cell have been studied. It is shown that EL measurements provide more reliable information about the behaviour of the IB material inside the IBSC structure than PL measurements. At low temperatures, the EL spectra are consistent with the quasi-Fermi level splits described by the IBSC model, whereas at room temperature they are not. This result is in agreement with previously reported analysis of the quantum efficiency of the solarcells

Influence of termal fluctuations in radiation damage cascade production and defect dynamics in tungsten

The detailed study of the deterioration suffered by the materials of the components of a nuclear facility, in particular those forming part of the reactor core, is a topic of great interest which importance derives in large technological and economic implications. Since changes in the atomic-structural properties of relevant components pose a risk to the smooth operation with clear consequences for security and life of the plant, controlling these factors is essential in any development of engineering design and implementation. In recent times, tungsten has been proposed as a structural material based on its good resistance to radiation, but still needs to be done an extensive study on the influence of temperature on the behavior of this material under radiation damage. This work aims to contribute in this regard. Molecular Dynamics (MD) simulations were carried out to determine the influence of temperature fluctuations on radiation damage production and evolution in Tungsten. We have particularly focused our study in the dynamics of defect creation, recombination, and diffusion properties. PKA energies were sampled in a range from 5 to 50 KeV. Three different temperature scenarios were analyzed, from very low temperatures (0-200K), up to high temperature conditions (300-500 K). We studied the creation of defects, vacancies and interstitials, recombination rates, diffusion properties, cluster formation, their size and evolution. Simulations were performed using Lammps and the Zhou EAM potential for W

Swift heavy ion damage to sodium chloride: synergy between excitation and thermal spikes

Systematic data on the effect of irradiation with swift ions (Zn at 735 MeV and Xe at 929 MeV) on NaCl single crystals have been analysed in terms of a synergetic two-spike approach (thermal and excitation spikes). The coupling of the two spikes, simultaneously generated by the irradiation, contributes to the operation of a non-radiative exciton decay model as proposed for purely ionization damage. Using this scheme, we have accounted for the π-emission yield of self-trapped excitons and its temperature dependence under ion-beam irradiation. Moreover, the initial production rates of F-centre growth have also been reasonably simulated for irradiation at low temperatures ( < 100 K), where colour centre annealing and aggregation can be neglected.

Germination ecology of the perennial Centaurium somedanum, a specialist species of mountain springs

To improve understanding of how a rare endemic species of Centaurium adapts to a specialized ecological niche, we studied the germination ecology of the mountain spring specialist, C. somedanum, a perennial species restricted to an unusual habitat for this genus. We conducted laboratory experiments with fresh seeds collected from two populations for three consecutive years, to investigate: (1) the effect of temperature and light ongermination; (2) the existence of seed dormancy; and (3) inter-population and inter-annual variation in germinability. Germination occurred only in the light and at relatively low temperatures (15?228C) with no differences between constant and alternating regimes, and a significant decrease at high temperatures (258C and 308C). We found non-deep simple morphophysiological dormancy and variation in seed germinability depending on the year of seed collection. C. somedanum diverged from the common germination characteristics of the genus in: (1) its germination at lower temperatures, which contrasts with what is generally expected in wetland species but could be adaptive in the spring habitat; and (2) its morphophysiological dormancy, which we report here for the first time in the genus and which could be an adaptation to its mountain habitat.

CCSD(T) Study of CD3-O-CD3 and CH3-O-CD3 Far-Infrared Spectra

From a vibrationally corrected 3D potential energy surface determined with highly correlated ab initio calculations (CCSD(T)), the lowest vibrational energies of two dimethyl-ether isotopologues, 12CH3–16O–12CD3 (DME-d3) and 12CD3–16O–12CD3 (DME-d6), are computed variationally. The levels that can be populated at very low temperatures correspond to the COC-bending and the two methyl torsional modes. Molecular symmetry groups are used for the classification of levels and torsional splittings. DME-d6 belongs to the G36 group, as the most abundant isotopologue 12CH3–16O–12CH3 (DME-h6), while DME-d3 is a G18 species. Previous assignments of experimental Raman and far-infrared spectra are discussed from an effective Hamiltonian obtained after refining the ab initio parameters. Because a good agreement between calculated and experimental transition frequencies is reached, new assignments are proposed for various combination bands corresponding to the two deuterated isotopologues and for the 020 → 030 transition of DME-d6. Vibrationally corrected potential energy barriers, structural parameters, and anharmonic spectroscopic parameters are provided. For the 3N – 9 neglected vibrational modes, harmonic and anharmonic fundamental frequencies are obtained using second-order perturbation theory by means of CCSD and MP2 force fields. Fermi resonances between the COC-bending and the torsional modes modify DME-d3 intensities and the band positions of the torsional overtones.

Understanding the operation of quantum dot intermediate band solar cells

In this paper, a model for intermediate band solar cells is built based on the generally understood physical concepts ruling semiconductor device operation, with special emphasis on the behavior at low temperature. The model is compared to JL-VOC measurements at concentrations up to about 1000 suns and at temperatures down to 20 K, as well as measurements of the radiative recombination obtained from electroluminescence. The agreement is reasonable. It is found that the main reason for the reduction of open circuit voltage is an operational reduction of the bandgap, but this effect disappears at high concentrations or at low temperatures.

Quantum molecular dynamics and ab initio studies of the crystal structure of hydrogen and deuterium

Hydrogen isotopes play a critical role both in inertial and magnetic confinemen Nuclear Fusion. Since the preferent fuel needed for this technology is a mixture of deuterium and tritium. The study of these isotopes particularly at very low temperatures carries a technological interest in other applications. The present line promotes a deep study on the structural configuration that hydrogen and deuterium adopt at cryogenic temperatures and at high pressures. Typical conditions occurring in present Inertial Fusion target designs. Our approach is aims to determine the crystal structure characteristics, phase transitions and other parameters strongly correlated to variations of temperature and pressure.

Ab initio Methodology for Calculating Elastic Constant and Sound Velocity for Hydrogen and Deuterium in Molecular Solid Phase

Hydrogen isotopes play a critical role both in inertial and magnetic confinement Nuclear Fusion. Since the preferent fuel needed for this technology is a mixture of deuterium and tritium. The study of these isotopes particularly at very low temperatures carries a technological interest in other applications. The present line promotes a deep study on the structural configuration that hydrogen and deuterium adopt at cryogenic temperatures and at high pressures. Typical conditions occurring in present Inertial Fusion target designs. Our approach is aims to determine the crystal structure characteristics, phase transitions and other parameters strongly correlated to variations of temperature and pressure. With this results is possible calculated the elastic constant and sound velocity for hydrogen and deuterium in molecular solid phase.

Dry cooling with night cool storage to enhance solar power plants performance in extreme conditions areas

Solar thermal power plants are usually installed in locations with high yearly average solar radiation, often deserts. In such conditions, cooling water required for thermodynamic cycles is rarely available. Moreover, when solar radiation is high, ambient temperature is very high as well; this leads to excessive condensation temperature, especially when air-condensers are used, and decreases the plant efficiency. However, temperature variation in deserts is often very high, which drives to relatively low temperatures during the night. This fact can be exploited with the use of a closed cooling system, so that the coolant (water) is chilled during the night and store. Chilled water is then used during peak temperature hours to cool the condenser (dry cooling), thus enhancing power output and efficiency. The present work analyzes the performance improvement achieved by night thermal cool storage, compared to its equivalent air cooled power plant. Dry cooling is proved to be energy-effective for moderately high day–night temperature differences (20 °C), often found in desert locations. The storage volume requirement for different power plant efficiencies has also been studied, resulting on an asymptotic tendency.

Highly correlated ab initio study of the far infrared spectra of methyl acetate

Highly correlated ab initio calculations (CCSD(T)) are used to compute gas phase spectroscopic parameters of three isotopologues of the methyl acetate (CH3COOCH3, CD3COOCH3, and CH3COOCD3), searching to help experimental assignments and astrophysical detections. The molecule shows two conformers cis and trans separated by a barrier of 4457 cm−1. The potential energy surface presents 18 minima that intertransform through three internal rotation motions. To analyze the far infrared spectrum at low temperatures, a three-dimensional Hamiltonian is solved variationally. The two methyl torsion barriers are calculated to be 99.2 cm−1 (C–CH3) and 413.1 cm−1 (O–CH3), for the cis-conformer. The three fundamental torsional band centers of CH3COOCH3 are predicted to lie at 63.7 cm−1 (C–CH3), 136.1 cm−1 (O–CH3), and 175.8 cm−1 (C–O torsion) providing torsional state separations. For the 27 vibrational modes, anharmonic fundamentals and rovibrational parameters are provided. Computed parameters are compared with those fitted using experimental data.

Experimental verification of intermediate band formation on titanium-implanted silicon

Intermediate band formation on silicon layers for solar cell applications was achieved by titanium implantation and laser annealing. A two-layer heterogeneous system, formed by the implanted layer and by the un-implanted substrate, was formed. In this work, we present for the first time electrical characterization results which show that recombination is suppressed when the Ti concentration is high enough to overcome the Mott limit, in agreement with the intermediate band theory. Clear differences have been observed between samples implanted with doses under or over the Mott limit. Samples implanted under the Mott limit have capacitance values much lower than the un-implanted ones as corresponds to a highly doped semiconductor Schottky junction. However, when the Mott limit is surpassed, the samples have much higher capacitance, revealing that the intermediate band is formed. The capacitance increasing is due to the big amount of charge trapped at the intermediate band, even at low temperatures. Ti deep levels have been measured by admittance spectroscopy. These deep levels are located at energies which vary from 0.20 to 0.28?eV below the conduction band for implantation doses in the range 1013-1014 at./cm2. For doses over the Mott limit, the implanted atoms become nonrecombinant. Capacitance voltage transient technique measurements prove that the fabricated devices consist of two-layers, in which the implanted layer and the substrate behave as an n+/n junction.

Enhanced thermionic currents by non equilibrium electron population of metals

An analytical expression is derived for the electron thermionic current from heated metals by using a non equilibrium, modified Kappa energy distribution for electrons. This isotropic distribution characterizes the long high energy tails in the electron energy spectrum for low values of the index ? and also accounts for the Fermi energy for the metal electrons. The limit for large ? recovers the classical equilibrium Fermi-Dirac distribution. The predicted electron thermionic current for low ? increases between four and five orders of magnitude with respect to the predictions of the equilibrium Richardson-Dushmann current. The observed departures from this classical expression, also recovered for large ?, would correspond to moderate values of this index. The strong increments predicted by the thermionic emission currents suggest that, under appropriate conditions, materials with non equilibrium electron populations would become more efficient electron emitters at low temperatures.

Uncovering cold disruption of the circadian clock in poplar

Dormancy is an adaptive mechanism that allows woody plants to survive at low temperatures during the winter. Disruption of circadian clock genes in winter or under low temperatures, both in long days as in short days, were described in our group few years ago (Ramos et al., 2005). Basic mechanisms of the circadian clock function are similar in herbaceous as well as in woody plants although there are differences in their response to low temperatures (Bieniawska et al., 2008). Woody plants growing in daylight conditions should have a specific transcriptional control above the circadian clock genes, which is responsible of their constitutive transcriptional activation observed under low temperatures conditions. In order to understand this regulatory process, we are analyzing the behavior of a circadian clock gene in poplar. To this aim, we have isolated its promoter region and fused to the luciferase reporter gene. This construct has been transformed into Populus tremula x P. alba 717-1B4 INRA clone. Here we present the characterization of these transgenic lines under different conditions of light and temperature.

Development of an Elevated Temperature Loop Heat Pipe for Space Applications and Investigation of Non Condensable Gas Impact on its Performance

Un caloducto en bucle cerrado o Loop Heat Pipe (LHP) es un dispositivo de transferencia de calor cuyo principio de operación se basa en la evaporación/condensación de un fluido de trabajo, que es bombeado a través de un circuito cerrado gracias a fuerzas de capilaridad. Gracias a su flexibilidad, su baja masa y su mínimo (incluso nulo) consumo de potencia, su principal aplicación ha sido identificada como parte del subsistema de control térmico de vehículos espaciales. En el presente trabajo se ha desarrollado un LHP capaz de funcionar eficientemente a temperaturas de hasta 125 oC, siguiendo la actual tendencia de los equipos a bordo de satélites de incrementar su temperatura de operación. En la selección del diseño optimo para dicho LHP, la compatibilidad entre materiales y fluido de trabajo se identificó como uno de los puntos clave. Para seleccionar la mejor combinación, se llevó a cabo una exhaustiva revisión del estado del arte, además de un estudio especifico que incluía el desarrollo de un banco de ensayos de compatibilidad. Como conclusión, la combinación seleccionada como la candidata idónea para ser integrada en el LHP capaz de operar hasta 125 oC fue un evaporador de acero inoxidable, líneas de titanio y amoniaco como fluido de trabajo. En esa línea se diseñó y fabricó un prototipo para ensayos y se desarrolló un modelo de simulación con EcosimPro para evaluar sus prestaciones. Se concluyó que el diseño era adecuado para el rango de operación definido. La incompatibilidad entre el fluido de trabajo y los materiales del LHP está ligada a la generación de gases no condensables. Para un estudio más detallado de los efectos de dichos gases en el funcionamiento del LHP se analizó su comportamiento con diferentes cantidades de nitrógeno inyectadas en su cámara de compensación, simulando un gas no condensable formado en el interior del dispositivo. El estudio se basó en el análisis de las temperaturas medidas experimentalmente a distintos niveles de potencia y temperatura de sumidero o fuente fría. Adicionalmente, dichos resultados se compararon con las predicciones obtenidas por medio del modelo en EcosimPro. Las principales conclusiones obtenidas fueron dos. La primera indica que una cantidad de gas no condensable más de dos veces mayor que la cantidad generada al final de la vida de un satélite típico de telecomunicaciones (15 años) tiene efectos casi despreciables en el funcionamiento del LHP. La segunda es que el principal efecto del gas no condensable es una disminución de la conductancia térmica, especialmente a bajas potencias y temperaturas de sumidero. El efecto es más significativo cuanto mayor es la cantidad de gas añadida. Asimismo, durante la campaña de ensayos se observó un fenómeno no esperado para grandes cantidades de gas no condensable. Dicho fenómeno consiste en un comportamiento oscilatorio, detectado tanto en los ensayos como en la simulación. Este efecto es susceptible de una investigación más profunda y los resultados obtenidos pueden constituir la base para dicha tarea. ABSTRACT Loop Heat Pipes (LHPs) are heat transfer devices whose operating principle is based on the evaporation/condensation of a working fluid, and which use capillary pumping forces to ensure the fluid circulation. Thanks to their flexibility, low mass and minimum (even null) power consumption, their main application has been identified as part of the thermal control subsystem in spacecraft. In the present work, an LHP able to operate efficiently up to 125 oC has been developed, which is in line with the current tendency of satellite on-board equipment to increase their operating temperatures. In selecting the optimal LHP design for the elevated temperature application, the compatibility between the materials and working fluid has been identified as one of the main drivers. An extensive literature review and a dedicated trade-off were performed, in order to select the optimal combination of fluids and materials for the LHP. The trade-off included the development of a dedicated compatibility test stand. In conclusion, the combination of stainless steel evaporator, titanium piping and ammonia as working fluid was selected as the best candidate to operate up to 125 oC. An LHP prototype was designed and manufactured and a simulation model in EcosimPro was developed to evaluate its performance. The first conclusion was that the defined LHP was suitable for the defined operational range. Incompatibility between the working fluid and LHP materials is linked to Non Condensable Gas (NCG) generation. Therefore, the behaviour of the LHP developed with different amounts of nitrogen injected in its compensation chamber to simulate NCG generation, was analyzed. The LHP performance was studied by analysis of the test results at different temperatures and power levels. The test results were also compared to simulations in EcosimPro. Two additional conclusions can be drawn: (i) the effects of an amount of more than two times the expected NCG at the end of life of a typical telecommunications satellite (15 years) is almost negligible on the LHP operation, and (ii) the main effect of the NCG is a decrease in the LHP thermal conductance, especially at low temperatures and low power levels. This decrease is more significant with the progressive addition of NCG. An unexpected phenomenon was observed in the LHP operation with large NCG amounts. Namely, an oscillatory behaviour, which was observed both in the tests and the simulation. This effect provides the basis for further studies concerning oscillations in LHPs.

Modelización de las propiedades radiativas e interacción de láseres ultraintensos con la materia

Desde el año 2004 el código ARWEN ha sido utilizado con éxito para simular y diseñar experimentos relacionados con blancos para fusión por confinamiento inercial [146], astrofísica de laboratorio [145], plasmas como amplificadores de láseres de rayos X [107] o plasmas creados por láser para la medición de espectros de transmisión. Para la realización de estas simulaciones es necesario, además de métodos de alto orden precisos y que presenten buenas propiedades conservativas, conocer ciertas propiedades de los plasmas. En el caso de la fluidodinámica y la conducción electrónica necesitaremos conocer la ecuación de estado [94, 49, 36], y para el transporte de la radiación será preciso disponer de los datos de absorción y emisión [104, 95, 40]. Hasta el año 2009 ARWEN dependía de códigos externos para la generación de estas tablas de opacidad, careciendo de control sobre los métodos empleados para su generación. Además estos códigos asumían equilibrio local termodinámico (LTE), limitando su validez a rangos de alta densidad y baja temperatura. En el marco de esta tesis se ha desarrollado el código BIGBART para la generación de tablas detalladas de opacidad y emisividad para su uso en el módulo de transporte de radiación. De esta forma el grupo dispondrá de su propia herramienta de generación de propiedades radiativas. El código desarrollado es capaz de tratar plasmas en estado fuera de equilibrio (non-LTE) mediante el modelo colisional-radiativo, extendiendo así el rango de validez de las tablas generadas. El trabajo desarrollado para implementar un código LTE/non-LTE estacionario es el siguiente Cálculo de estructura y datos atómicos. Se ha acoplado en código FAC a BIGBART, incorporando la capacidad para generar potenciales atómicos para una configuración y el cálculo de funciones de onda de electrones en orbitales ligados y libres. Aproximaciones y métodos para la obtención de tasas y secciones eficaces de procesos. Se han incluido y programado los modelos implementados en FAC para el cálculo de secciones eficaces de fotoionización, y tasas de decaimiento de emisión espontánea y autoionización. Además se ha incluido el modelo Plane-Wave Born (PWBA) para el cálculo de las secciones eficaces de ionización y excitación colisional. Modelos para la obtención de la distribución de estados iónicos dentro del plasma. Se ha programado un solver LTE basado en la ecuación de Saha-Boltzmann con efectos de ionización por presión debida a los iones adyacentes. También se ha implementado un modelo non-LTE colisionalradiativo para la resolución del sistema de ecuaciones que nos permite obtener la densidad de estados iónicos fuera de equilibrio. Modelo non-LTE RADIOM. Se ha implementado el modelo RADIOM para aproximar efectos de no-equilibrio mediante cálculos LTE a una temperatura equivalente, menor o igual que la temperatura electrónica real. Cálculo de las propiedades espectrales de absorción y emisión. Se han implementado los modelos para el cálculo de los perfiles espectrales de absorción y emisión para procesos entre niveles ligados, ligado-libre y librelibre. Aprovechando el trabajo realizado en este sentido, durante el transcurso de esta tesis se amplió el código BIGBART para tratar problemas con dependencia temporal. La extensión para tratar este tipo de problemas se orientó a la simulación numérica de la interacción de láseres ultra intensos en el rango XUV/rayos X. Para ello, además de adaptar el modelo non-LTE colisionalradiativo se incluyeron procesos adicionales asociados a la interacción de la materia con fotones altamente energéticos. También se han incluido modelos para el cálculo de las propiedades ópticas, y por ende las propiedades dieléctricas de la materia irradiada, de gran interés en algunas aplicaciones novedosas de estos láseres intensos. Debido a la naturaleza fuertemente fuera de equilibrio en la interacción de fotones de alta energía con la materia, se incluyó el tratamiento de la distribución de electrones libres fuera de equilibrio en la aproximación de Fokker-Planck, tanto para condiciones degeneradas como no degeneradas. El trabajo desarrollado en el código non-LTE con dependencia temporal es el siguiente Procesos asociados a láseres intensos XUV/rayos X. Se ha implementado el cálculo de procesos radiativos estimulados de absorción y emisión por el láser. También se han incluido procesos asociados a la creación de vacantes en capas internas electrónicas (Shake), además de doble autoionización y doble fotoionización. Cálculo de propiedades ópticas y dieléctricas en blancos sólidos. Se ha implementado un modelo para la absorción por bremsstrahlung inverso en blancos en estado sólido. Con el coeficiente de extinción debido a procesos de fotoabsorción resonante, fotoionización y bremsstrahlung inverso se obtiene el ´ındice de refracción mediante la relación de Kronig-Kramers. Electrones fuera de equilibrio. Se ha tratado la evolución de la distribución de electrones, cuando no está justificado asumir que es Maxwelliana o de Fermi-Dirac, mediante la aproximación de Fokker-Planck para la colisión entre electrones libres. En la resolución de la ecuación de Fokker-Planck se han incluido los procesos inelásticos por colisiones con iones y términos fuente por interacción con el láser y otros procesos. ABSTRACT Since 2004 the ARWEN code has been successfully used to simulate and design targets for inertial confinement fusion experiments [146], laboratory astrophysics [145], plasmas as X-ray lasers amplifiers [107] or laser created plasmas for measuring transmission spectra. To perform these simulations it is necessary, in addition to high order precise methods with good conservative properties, to know certain properties of plasmas. For fluid dynamic and electronic conduction we need to know the equation of state [94, 49, 36], and for radiation transport it will be necessary to have the data of the absorption and emission [104, 95, 40]. Until 2009 ARWEN depended on external codes to generate these opacity tables, lacking of control over the methods used for their generation. Besides, these codes assumed local thermodynamic equilibrium (LTE), limiting their validity ranges to high densities and low temperatures. As part of this thesis it has been developed the BIGBART code for generating detailed opacity and emissivity tables for use in the radiation transport module. This group will have its own tool for the generation of radiative properties. The developed code is capable of treating plasmas out of equilibrium (non-LTE) by means of a collisional-radiative model, extending the range of validity of the generated tables. The work to implement an LTE/non-LTE steady-state code is as follows Calculation of structure and atomic data. the FAC code was coupled to BIGBART, incorporating the ability to generate atomic potentials for calculating configuration wave functions for bound and free electrons. Approaches and methods for obtaining cross sections and processes rates. We have included and reprogrammed in Fortran the models implemented in FAC for calculation of photoionization cross sections and decay rates of spontaneous emission and autoionization. We also included the Plane- Wave Born (PWBA) model to calculate the cross sections of ionization and collisional excitation. Models for the obtention of the distribution of ionic states within the plasma. We programmed a LTE solver based on the Saha-Boltzmann equation with pressure ionization effects due to adjacent ions. It has also been implemented a non-LTE collisional-radiative model for solving the system of equations that allows us to obtain the density of ionic states out of equilibrium. Non-LTE RADIOM model. We have implemented the non-LTE RADIOM model to approximate non-equilibrium effects with LTE data at an equivalent temperature, lower or equal to the actual electronic temperature. Calculation of the spectral absorption and emission properties. Models have been implemented for the calculation of the spectral profiles of absorption and emission processes between bound levels, free-bound and free-free. Taking advantage of the work done in this direction throughout the course of this thesis the code BIGBART was extended to treat time-dependent problems. The extension to treat such problems is oriented to the numerical simulation of the interaction of ultra intense lasers in the XUV/X-ray range. For this range, in addition to adapting the non-LTE collisional-radiative model, additional processes associated with the interaction of matter with high energy photons. We also included models for calculation of the optical properties, and therefore the dielectric properties of the irradiated material, of great interest in some novel applications of these intense lasers. Due to the strong non-equilibrium nature of the interaction of high energy photons with matter, we included the treatment of the distribution of free electrons out of equilibrium in the Fokker-Planck approximation for both degenerate and non-degenerate conditions. The work in the non-LTE time-dependent code is as follows Processes associated with intense XUV/X-ray lasers. We have implemented the calculation of stimulated radiative processes in absorption and emission. Also we included processes associated with the creation of electronic vacancies in inner shells (Shake), double autoionization and double photoionization. Calculation of optical and dielectric properties in solid targets. We have implemented a model for inverse bremsstrahlung absorption in solid targets. With the extinction coefficient from resonant photoabsorption, photoionization and inverse bremsstrahlung the refractive index is obtained by the Kramers-Kronig relation. Electrons out of equilibrium. We treat the evolution of the electron distribution, when it is not justified to assume a Maxwellian or Fermi-Dirac distribution, by the Fokker-Planck approximation for collisions between electrons. When solving the Fokker-Planck equation we included inelastic collision processes with ions and source terms by interaction with the laser and other processes.