Properties of binary oxides: a DFT study
Thesis event information
Date and time of the thesis defence
Place of the thesis defence
Linnanmaa, hall TA105 (Arina Hall)
Topic of the dissertation
Properties of binary oxides: a DFT study
Doctoral candidate
Master of Science Olga Miroshnichenko
Faculty and unit
University of Oulu Graduate School, Faculty of Science, Nano and Molecular Systems Research Unit
Subject of study
Theoretical Physics
Opponent
Professor Adam Kiejna, University of Wrocław, Poland
Custos
Professor Matti Alatalo, University of Oulu
Properties of binary oxides have been explored theoretically giving insight into the effect of environment
One particular binary oxide, titanium dioxide or TiO2, is used in an enormous amount of applications across different fields. Due to its refractive properties, relatively large TiO2 particles are used as pigments. TiO2 is used in virtually everything that has a white color. Very small particles are used, for example, in sunscreens and as catalysts. By changing the size, properties of particles are also changing, and they become more sensitive to their structure, size, and environment.
In this dissertation, the effect of SO4 and OH groups on the properties of very small (1-2 nanometers) TiO2 particles was studied by quantum mechanical calculations. These groups are present on the surface during manufacturing. It was found that the abovementioned groups change properties of particles, altering their geometrical structure as well as electronic, which is reflected in their optical properties. These effects should be taken into account in quality control and when comparing computed data with experimental.
The second part of the dissertation is dealing with computed partial charges of atoms in binary oxides and their oxidation states. Partial charges show the distribution of electrons among atoms and they are relatively easy obtained from quantum mechanical electronic structure calculations. Oxidation state is a theoretical concept that identifies how many electrons an atom has gained or lost. It has been debatable whether these two concepts have a correlation. The conducted research shows that connection between them exists by analyzing thousands of records of data for binary oxides from open materials databases. This correlation enables fast oxidation state estimation and therefore accelerates scientific discovery.
In this dissertation, the effect of SO4 and OH groups on the properties of very small (1-2 nanometers) TiO2 particles was studied by quantum mechanical calculations. These groups are present on the surface during manufacturing. It was found that the abovementioned groups change properties of particles, altering their geometrical structure as well as electronic, which is reflected in their optical properties. These effects should be taken into account in quality control and when comparing computed data with experimental.
The second part of the dissertation is dealing with computed partial charges of atoms in binary oxides and their oxidation states. Partial charges show the distribution of electrons among atoms and they are relatively easy obtained from quantum mechanical electronic structure calculations. Oxidation state is a theoretical concept that identifies how many electrons an atom has gained or lost. It has been debatable whether these two concepts have a correlation. The conducted research shows that connection between them exists by analyzing thousands of records of data for binary oxides from open materials databases. This correlation enables fast oxidation state estimation and therefore accelerates scientific discovery.
Last updated: 1.3.2023