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Crystal and molecular structure study of garnets from selected localities of the České středohoří Mts.
Píšová, Barbora ; Skála, Roman (advisor) ; Laufek, František (referee)
Major and minor element contents of garnets from mantle peridotites and eclogites brought to the surface by volcanic rocks of the České středohoří Mts. were determined by an electron probe microanalyzer. Garnets are homogenous and their chemical composition corresponds to solid solution containing 65-71 % pyrope, other end members significantly present are almandine, uvarovite and grosulare. This method also help to discover polyphase inclusions chemically corresponding to amphiboles (pargasite, cummingtonite, magnesio-hornblende and katophorite). Next to amphiboles following minerals were found in inclusions: omphacite, carbonates, phlogopite, clinochlore, olivine, apatite, spinel group minerals, and sulfidic phases potentially close to pentlandite. Samples were also analyzed by powder X-ray diffraction. Qualitative phase analysis confirmed pyrope homogeneity. The refinement of crystal structure parameters was performed by the Rietveld method. Raman microspectroscopy showed shifts of individual bands in the Raman spectra compared to those of pure pyrope. Position of bands in spectra differs due to the substitution of Ca for Mg at the dodecahedral sites of the structure. Mutual positive correlations among elements Cr, Ca, Mg, Al, Si, Mn, Ti and Na were observed. Correlations were found also between...
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Synthesis and study of crystalline materials for NLO
Janatková, Tereza ; Němec, Ivan (advisor) ; Vojtíšek, Pavel (referee)
This thesis is focused on preparation and study of new compounds of chosen organic bases with potential use in nonlinear optics. 2-amino-5-nitropyrimidine, 2-amino-4-methylpyrimidine and their salts with inorganic and organic acids are compounds of the main interest. Diffraction and vibrational-spectroscopic methods of characterization were used in combination with quantum chemical calculation methods. Another aim of this thesis was preparation of new salts of chosen pyrimidine derivates with the use of methylsulphonic acid. Part of this section is devoted to completion of pyridinium methylsulphonate phase transition and nonlinear optical property studies.
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Molecular crystals for NLO applications - compounds of 1H-pyrazole-carboxamidine
Kohúteková, Soňa ; Němec, Ivan (advisor) ; Šloufová, Ivana (referee)
Title: Molecular crystals for NLO applications - compounds of 1H-pyrazole-carboxamidine Author: Bc. Soňa Kohúteková Department: Department of Inorganic Chemistry Supervisor: prof. RNDr. Ivan Němec, Ph.D. Abstract: The aim of this diploma thesis is preparation and characterisation of novel compounds of 1H-pyrazole-carboxamidine in consideration of their potential application in the field of nonlinear optics. This thesis is focused on preparation of crystalline salts or adducts combining 1H-pyrazole-carboxamidine with selected inorganic and organic acids. Prepared materials were characterised mainly by the means of vibrational spectroscopy and X-ray diffraction analysis. Quantum-chemical calculations were used for a prediction of nonlinear optical properties as well as for interpretation of measured vibrational spectra. Four different approaches of calculations were used for an optimisation of computing time together with accuracy of the fit of calculated and measured spectra. Finally, measurements of second harmonic generation efficiency of two powder samples with non-centrosymmetric crystal structures were performed. Key words: NLO, vibrational spectroscopy, crystal structure, quantum-chemical calculations
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Characterization of proteins of 2'-5' oligoadenylate pathway by means of vibrational spectroscopy
Víšová, Ivana ; Kopecký, Vladimír (advisor) ; Bednárová, Lucie (referee)
The work concerns to structural characterization of two important proteins of 2'-5' oligoadenylate pathway participating in an immune response of organism to a viral infection. Studied proteins were ankyrin domain of mouse RNase L, the C-terminal part of human phosphodiesterase 12 and the complete human phosphodiesterase 12. The proteins were characterized by Raman spectroscopy, infrared spectroscopy, electronic circular dichroism, dynamic light scattering and in addition by two non-spectroscopic methods- differential calorimetry and electrophoresis. For each protein the secondary structures, thermal stability, weight of oligomers and generally a basic characterization by above mentioned methods were provided.
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Salts of heteroaromatic compounds for NLO
Basová, Miriam ; Němec, Ivan (advisor) ; Kubíček, Vojtěch (referee)
The main target of this bachelor's thesis is the preparation and characterization of novel compounds with expected non-linear optical properties. Starting material for the preparation of new salts was 2,4-diamino-1,3,5-triazine. These salts or co-crystals were prepared by the crystallization with selected inorganic and organic acids. The methods of infrared and Raman spectroscopy along with X-ray diffraction methods were used to characterize the prepared materials. Moreover, the NLO potential of selected molecules was proven by quantum − chemical calculations. These calculations were also used for the interpretation of the vibrational spectra. Finally, the structures with non-centrosymmetric assembly were examined for the second harmonic generation efficiency in powdered samples. Keywords: non-linear optics, 2,4-diamino-1,3,5-triazine, vibrational spectroscopy, structural analysis
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Application of vibrational spectroscopy in the study of violacein pigment
Váňová, Hana ; Němec, Ivan (advisor) ; Šmejkal, Petr (referee)
This thesis deals with the study of microbial pigment violacein in the real sample of lyophilized microorganisms. The sample was investigated by using methods of vibrational spectroscopy with focusing on the applicability of surface enhanced and resonance micro-Raman spectroscopy. For this purpose several different systems for enhancing Raman intensity together with the set of excitation lasers emitting in the visible light region were used. The conclusion of this thesis are the recommendations connected with the appropriateness of using each amplifying systems and excitation wavelengths for the successful identification of violacein pigment in the sample. Powered by TCPDF (www.tcpdf.org)
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Nové molekulární materiály pro nelineární optiku - příprava a detailní charakterizace
Mathauserová, Jana ; Němec, Ivan (advisor) ; Gyepes, Róbert (referee)
In this thesis both an experimental and computational study of selected prospective materials for nonlinear optics is presented. The main focus was put on 2-aminopyrimidinium hydrogen- phosphite (AMPPO3), a salt with high SHG efficiency and Type I. phase matching properties. AMPPO3 had been studied by our research group and its favourable qualities such as easy preparation, colourlessness, great water solubility and good crystallinity motivated further in- terest and the attempts for the growth of bulk single crystals from thermostated aqueous solu- tions as presented here. The products are meant to be probed by laser in a specific direction to determine the maximum SHG efficiency, so far the polarized microscopy study revealing the extreme dispersion effects is provided. AMPPO3 is an example of H-bond stabilized framework with both organic and inorganic building blocks. The computational study was led as to understand the structure which is typical for one of the classes of compounds exhibiting nonlinear optical properties. DFT implemented in parallel CP2K was used and for the comparison three other optically active materials of sim- ilar composition were studied - urea, guanylurea hydrogenphosphite and 2-aminopyrimidine- boric acid 3/2 cocrystal. After the constrained geometry optimization and cell...
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Analysis of organic additives in historical mortars
Křížová, Iva ; Čabala, Radomír (advisor) ; Hynek, Radovan (referee)
- 4 - Abstrakt The aim of this diploma thesis was to determine the possibility of identifying the protein and lipid additives, such as blood, gelatine, curd, lard and eggs, in the model samples of lime based mortars using Raman spectroscopy and gas chromatography- mass spectrometry. It was proved that the method of Raman spectroscopy can determine the presence of organic additives in the order of one weight percent. The gas chromatography enables to detect lipid additives from the order of hundredths weight percent. Unambiguous resolution of protein additives can be done in the samples with the concentrations up to the order of one weight percent of the additives.
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Preparation and characterization of novel molecular materials for nonlinear optics
Mathauserová, Jana ; Němec, Ivan (advisor) ; Nižňanský, Daniel (referee)
The main issue of this bachelor thesis is the investigation of salts and cocrystals of biuret and 2-aminopyrimidine in consideration of their usage in the field of nonlinear optics. The first attempt of this thesis was preparation of compounds combining biuret with organic or inorganic acids, urea and biguanide. The second part is focused on the searching of new salts of 2-aminopyrimidine and on further characterisation of its formerly prepared compounds. The methods employed to investigate the prepared materials include vibrational spectroscopy and X-ray diffraction analysis. The theoretical quantum mechanical calculations were used to predict the nonlinear optical properties of selected molecules and also for the interpretation of the recorded vibrational spectra. Measurements of second harmonic generation efficiency of selected powder samples were performed.
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Diagnostics of neurodegenerative diseases by means of Raman spectroscopy
Klener, Jakub ; Kopecký, Vladimír (advisor) ; Matějka, Pavel (referee)
Therapies of neurodegenerative diseases are often very difficult and their success depend on an early diagnose. From that reason we have been developing new diagnostic method for multiple sclerosis and Alzheimer disease by drop coating deposition Raman (DCDR) spectroscopy of cerebrospinal fluid (CSF) in this work. We found out conditions of measurements, where spectra were reproducible and accepted for standard diagnostic practices. We discovered that CSF has fast degradation at a room temperature, which was detectable in spectra after 5 hours, and degradation due to refreezing. DCDR spectra of CSF from individual patients were analyzed by factor and cluster analysis. Multiple sclerosis was manifested by lower intensity of a Raman band at 1080 cm−1 , which is probably connected with more general pathologic state. Spectral changes caused by Alzeheimer disease were more complex and beside changes mentioned above also changes connected with composition and conformation of proteins were identified in regions 1200-1800 cm−1 and 2870-2950 cm−1 . Additionally, we succeeded in distinguishing of young healthy patients from older patients in DCDR spectra. In this work were checked up, that DCDR is good diagnostic method for clinical practices for determining neurodegenerative diseases through the complex...
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