|
|
Calculations of photoelectron spectra of small water clusters using the independent molecule model
Šklíba, Pavel ; Mašín, Zdeněk (advisor) ; Čížek, Martin (referee)
The aim of this thesis is to investigate theoretically photoelectron spectra of small water molecular clusters. This work is motivated by the recent experimental results of Hartweg et al [Phys. Rev. Letters 118, 103402, 2017] which showed that with an increasing number of constituent molecules in the water cluster the asymmetry parameter characterizing the photoelectron angular distribution converges to a universal shape. At the moment there are no theoretical calculations to support this finding. Therefore, we have developed a very simple model of photoionization of molecular clusters based on the use of photoionization data for a single molecule. We have found that the results of our model are sensitive to the different conformations of the clusters. Some of our results for the photoelectron angular distribution exhibit trends observed in the experiment. Nevertheless, the validity of our model will have to be studied in the future with the help of accurate calculations before the results can be conclusively interpreted.
|
|
|
Časově rozlišená spektroskopie světlem indukovaných procesů
KUZNETSOVA, Valentyna
This Ph.D. thesis is devoted to the study of the photophysical properties of photosynthetic pigments. The brief introduction to the field is given in Chapter 1. In studies presented in the thesis, femtosecond pump-probe spectroscopy was used to determine the relation between the molecular structure of carotenoids and its spectroscopic properties. The experimental and data analysis methods are described in Chapter 2. Chapter 3 addresses the investigation of the effect of isomerization on excited-state dynamics of the carbonyl carotenoid fucoxanthin. In Chapter 4, the different response of carbonyl carotenoids to solvent proticity is used to estimate the structure of an unknown carotenoid from Chromera velia. In Chapter 5, spectroscopic properties of the S1 state of three linear carotenoids were studied after excess energy excitation in the S2 state. Chapter 6 presents a femtosecond spectroscopic comparison study of Orange and Red Carotenoid Proteins binding different carotenoids.
|
|
| |
|
| |
|
|
Excited state dynamics of carotenoids in solution and proteins
CHÁBERA, Pavel
Time resolved spectroscopy is one of the crucial methods used to study processes on molecular level in biological systems. It is useful especially for monitoring fast processes that take a place in photosynthetic apparatus of photosynthetic organisms, such as electron and energy transfer. The integral parts of photosynthetic apparatus are carotenoids, whose role in the photosynthetic apparatus is not as well explored as it is for chlorophylls. It was proved that carotenoids actively participate in energy transfer processes in photosynthetic antennas. They have a crucial role in protection against excess energy damage. They are also electron donors in both antennas and reaction centers. The fact that photo-physical properties of carotenoids are much different from properties of others organic pigments, complicates studies of their functions in photosynthesis as well as in other biological systems. This thesis employs advanced methods of femtosecond spectroscopy to obtain more information about carotenoid functions in some biological systems and in solution with special focus on carotenoids containing carbonyl group.
|
guest ::
