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FRINATEK-Fri prosj.st. mat.,naturv.,tek

Linear and Non-linear Response Properties and Spectroscopy of Solids from Relativistic TDDFT

Alternative title: Lineære og ikke-lineære responsegenskaper og spektroskopi av faste stoffer fra relativistisk tidsavhengig tetthetsfunksjonalteori

Awarded: NOK 3.6 mill.

Progress in technologies such as electronics, solar cells, and lasers requires new materials with favourable properties. The experimental discovery of these materials is a challenging task that has to be aided by theoretical understanding in combination with computer simulations. Usually, the computer simulations solve the quantum mechanical Schrödinger equation. They have been successful for predicting the properties of materials made of light elements such as carbon and hydrogen. However, many new and perspective materials contain heavy elements such as metals. For such heavy element-containing materials, the effects of the theory of relativity must be considered. This is achieved by solving the Dirac equation, a more complicated relativistic relative of the Schrödinger equation, instead. My project responds to the demand for a computer program for material science research that would describe the relativistic effects. I will develop a method based on the Dirac equation that will be able to describe electric and optical properties of materials. I will spend my mobility phase in Hamburg in the group of Angel Rubio that has ample experience in solid state physics, light-matter interactions, and program development. The outcome of my research will be program library that will be integrated into the quantum chemistry program ReSpect that is being developed at UiT. It will be made available for scientists working on the prediction of material properties to accelerate the progress in this research field.

ProSpectS is a project aimed at the development and applications of a novel computational methodology for the prediction of linear and second-order non-linear optical properties of solid-state materials. These spectroscopic properties are measured to characterize materials for applications in electronics, optics, or photonics. Moreover, the development of novel radiation sources such as X-ray free electron lasers drives the adoption of new types of spectroscopies based on ultrafast and multi-photon processes. These advances create demand for new theoretical tools able to predict and interpret the results of such experiments. ProSpectS aims to respond to this demand by delivering a computer program that will include relativistic effects in full four-component Dirac regime. This will enable its applicability for materials containing all elements across the periodic table including heavy elements. The combination of relativistic effects with all-electron description in localized basis sets will, in turn, ensure correct description of X-ray spectra. Finally, the damped response time dependent density functional theory approach to material properties will offer favourable balance between accuracy and computational cost and allow treatment of near-resonant, high-frequency, or high-density of states spectral regions.

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FRINATEK-Fri prosj.st. mat.,naturv.,tek