DESCRIPTION OF THE RESEARCH PROGRAMS
A1. Ambipolar Heterotruxenes as Materials for Organic Electronics
Prof. Marek Pietraszkiewicz in collaboration with
Prof. Regis Reau (CNRS-Universite de Rennes, France ),
Prof. Neil Robertson ( University of Edinburgh, Great Britain),
Prof. Ifor D. W. Samuel (University of St. Andrews, Great Britain),
Prof. J. A. Gareth Williams (Durham University, Great Britain)
Heterotruxenes consist of a fast developing class of ď'°-electronic molecules, such as low/wide band gap materials, NLO and photoluminescent materials, multiphoton absorption molecules, lasing materials, and liquid crystals components. These compounds are only accessible by multistep synthesis, but their electronic properties are very much superior over commercially available compounds. In particular, ambipolar truxenes containing electron donor or acceptor may display properties desirable in OLED technology and organic photovoltaics, expected to have profound impact on saving the electric energy and environment. This proposal consists on: 1) Computer-Assisted Design and synthesis of novel heterotruxenes, and their d,f metal ion complexes 2) molecular modeling and TD DFT and DFT calculations using ADF soft package, 3) physico-chemical characterization of novel compounds, in particular: a) UV-vis spectral properties, PL quantum yields and PL lifetimes, singlet/triplet levels calculations, solid-state photoluminescence b) fluorescence and phosphorescence, c) HOMO-LUMO calculations based on theoretical calculations and CV/spectral data, d) electron transfer phenomena within the molecule, e) transient absorbance phenomena, f) the optical properties of d,f-metal ion complexes, g) charge transport properties.
A2. Structure and NMR and UV spectra of strained cyclophanes with small bridges
Prof. Helena Dodziuk in collaboration with
Prof. Kenneth Ruud (Center for Theoretical and Computational Chemistry, Tromso University)
Cyclophanes with small bridges (like 1 - 3) are interesting objects in view of nonplanarity of their aromatic rings interacting with each other and a close distance between them on the one hand, and their prospective applications as monomers or polymers on the other. Better understanding of their structure and properties is of importance from the point of view of basic science and the applications. The studies would include [m,n]cyclophanes 2 with m n in which the average planes of the rings are not parallel, multibridged systems like superphane 3 and, eventually, their cyclodextrin complexes. The studies will include both experimental measurements and calculations of the structure and NMR parameters. In particular, temperature-dependent solid state NMR spectra showing dynamic behaviour of cyclophanes themselves and complexed with cyclodextrins will be studied.
A3. Excited-state intramolecular proton transfer (ESIPT) reactions in molecular beams: tunnelling and mode-selectivity
dr hab. Jerzy Sepiol in collaboration with
Dr Anne Zehnacker-Rentien (Laboratoire de Photophysique Moleculaire du CNRS, Universite de Paris-Sud, 91405 Orsay, Francja)
Compounds exhibiting the excited-state intramolecular proton transfer (ESIPT) reactions are very attractive as components of light emitting diodes, stabilizers of polymers, high-energy radiation detectors and bio-sensors. Studies on ESIPT reactions in solutions and in supersonic jets have already been curried out in the IPC PAS. Molecules of interest are porphycenes and bis-benzoxazolylphenols showing primary and phototautomeric fluorescence. Introducing small modification to molecular platform (e.g. by methyl substitution) one can modify the tunneling processes leading to molecular relaxation. Spectroscopic consequences of structural modification can be observed in specific conditions produced in supersonic molecular beams, where molecules of interest became cold. The purpose of the project is to measure the fluorescence excitation as well as dispersed fluorescence spectra, and to detect ions produced by highly energetic laser radiation, on two separate experimental arrangements in our Laboratory of Molecular Supersonic Beams.
A4, A5. Thermodynamic spin density functional and information theory as a tool to probing the interplay between electronic and geometric degrees of freedom in molecules and reactive systems.
prof. A. Holas, dr. R. Balawender in collaboration with
prof. P. Geerlings (Vrije Universiteit Brussel, Belgium),
prof. W. Yang (Duke University, USA),
prof. P.W. Ayers (McMaster University, Canada).
The project consists of the methodological part and the applied parts (inorganic /organic/biochemistry). The basic idea of this project is the electronic density as a source and a carrier of the information about molecular structure and reactivity. Chemical reactivity indices, the indispensable descriptors of ability of molecules to react chemically, will be reexamined applying rigorous foundations within the density functional theory (DFT) and the thermodynamic spin extension of it (TSDFT). Recent developments in the last approach to molecules and their constituent fragments will be deeply explored. In particular, the entropic representation description provided by the information theory (IT) and the elements of the communication system approach to the chemical bond multiplicities will be used. Fundamental work on the development of TSDFT- and IT-based descriptors of the molecular charge distribution and the chemical reactivity will be tested.
A6. Spin transfer and relaxation in magnetic nanostructures
Applied part will be realized in two Ph.D. Projects:
I(in A4). Theoretical thermochemistry for radicals in the framework of TSDFT and IT.
The thermochemistry for radicals will be a case for testing theoretical predictions in organic and inorganic chemistry, both on gas phase and solution systems. Small size of a radical and its open-shell electronic structure predestine it to be a convenient object for testing TSDFT indices and to study the influence of the fractional charge and spin on the performance of approximate functionals and the exact exchange method.
II(in A5). Prediction of the carcinogenic effect of polycyclic aromatic hydrocarbons using TSDFT reactivity indices.
Efforts in biochemistry will be focused on the prediction of the carcinogenic effect of polycyclic aromatic hydrocarbons (PAHs). In order to exert their genotoxic effects, PAHs require conversion into electrophilically reactive derivative. Some number of potential reactions of the electrophilically reactive metabolites of PAHs with cellular nucleophiles makes them appropriate for testing the region-selective indices like the Fukui function, the local softness, the nuclear Fukui function, etc.
Dr hab. Marek Cinal in collaboration with
Prof. David M. Edwards (Imperial College of Science, Technology and Medicine, London, Great Britain)
Dr. Andrey Umerski (Open University, Milton Keynes, Great Britain)
The aim of the proposed study is a quantum-mechanical description of processes that determine the dynamics of magnetization in ferromagnetic metallic nanowires and ultrathin films. The research will be focused on magnetic relaxation (via Gilbert damping and other relevant mechanisms) and its relation to spin-orbit coupling (SOC), and on spin-transfer torque due to an electric current carried by the system. The systems investigated will include iron and permalloy flat nanowires as well as Fe and Co thin films, both types of systems being unsupported or located on a substrate with large SOC, like Pd and Pt. The obtained results will be compared with experimental data on nanowire domain-wall velocities. This work is applicable to a wide variety of potential spintronic devices - such as MRAM, magnetic domain racetrack memories and logic devices - and the results of the calculations should aid the design of systems with parameters which optimize their performance.
A7. Feedback and teaching in reaction-diffusion information processing
Prof. Jerzy Gorecki in collaboration with Prof. Kenichi Yoshikawa (Department of Physics, Kyoto University),
Prof. Marcus Hauser (Abteilung Biophysik, Institut fuer Experimentelle Physik Otto-von-Guericke-Universitat Magdeburg)
Excitable chemical medium can be applied for information processing. All information processing executed by living organisms is based on chemistry. The proposed Ph.D. project is focused on increasing the flexibility of information processing with reaction-diffusion medium. We plan to design chemical computing systems that are able to modify their functions in the process of learning. In the project we will use Bielousov-Zhabotynski reaction as a computing medium. The student is expected to design, build and program an experimental setup within which the state of computing medium can be analyzed. A set of cameras linked to a computer will process images of the medium in the real time. The student will investigate different methods (local illumination, local change of electric field, local flows) of influencing the time evolution of the medium and write computer programs that control the applied stimuli. This feedback will be used as a training tool to teach the medium to perform a selected function. The design of training strategy will be based on procedures similar to those used in genetic programming. It is expected that obtained results will help to determine the structure of the medium for which the process of training can be performed in the most efficient way. Within the project we also determine the constraints necessary for keeping the information processing properties for a long time.
A8. Stochastic effects in far-from-equilibrium chemical systems
Dr hab. Bogdan Nowakowski in collaboration with
Dr. habilite Annie Lemarchand (Universite Pierre et Marie Curie, Paris, France)
Fluctuations significantly change dynamics of far-from-equilibrium chemical systems, which may exhibit bistability, excitability or oscillations. The stochastic effects are particularly important in nanosystems which contain small number of particles. Chemical reactions induce deviation from the Maxwellian form of the particle velocity distribution, which can be detected only in microscopic simulations. Perturbation of Maxwellian distribution in turn modifies rate constants of chemical reactions, for which approximate analytical solutions can be derived from the Boltzmann equation. The existing results of microscopic simulations indicate that such effects lead to changes from mono- to bi-stability, or to emergence of excitability. The purpose of this work is derivation of the form of the master equation which includes the nonequilibrium contributions to the rate constants related to perturbation of velocity distribution. The developed master equation will allow to include the effect appearing at molecular level in the widely accepted method of mesoscopic simulations which are much more efficient than the microscopic approach. The equation will be verified by comparing mesoscopic simulations obtained by the Gillespie algorithm with the microscopic simulations of gas systems.
A9. Stability of patterns in nonlinear two variable excitable chemical systems
Prof. Andrzej Kawczynski in collaboration with
Prof. Lutz Schimansky-Geier (Humboldt Universitat, Berlin, Germany)
Prof. Irving R. Epstein (Brandeis University, Waltham, USA)
Internal fluctuations may induce change of spatiotemporal patterns (dissipative structures - DS) in macroscopic nonlinear reaction-diffusion (RD) systems, which exhibit the coexistence of DS, as well as in the systems close to bifurcations. The effect is particularly strong in nanometric scale DS. The aim of the thesis is to study influence of internal fluctuations on the stability of RD spatiotemporal patterns in two variable excitable systems with three stationary states. Three approaches will be compared: the master equation, the Fokker-Planck equation and the Langevin equation with white noise term. The studies will be concentrated on one dimensional systems. The RD equations are strongly nonlinear and their solutions can be obtained by numerical calculations. In these calculations the fourth order Runge-Kutta and the Cranck-Nicolson algorithm will be used. The Gillespie algorithm will be used in the master equation approach. The Fokker-Planck equations will be solved by the standard numerical methods. The Langevin equations will be also solved numerically by using the Stratonovich and/ or the Ito algorithm to the noisy terms.
A10. Lyotropic cubic liquid crystals - from cubosomes to small monocrystals
Dr hab. Wojciech. T. Gozdz in collaboration with
Prof. Pawel Pieranski (Universite Paris Sud, CNRS, Orsay, France)
Amphiphilic molecules in aqueous solutions self-assemble into variety of lyotropic liquid crystal phases. In the bicontinuous inverted phases the molecules self-assemble into a liquid bilayer which separates two interwoven labyrinths filled with water. In cubic phases the bilayers have ordered shapes of infinite periodic minimal surfaces, while in the sponge phase the shape of the bilayer displays a short range order. Due to their topology and liquid- or crystal-like symmetries, the bicontinuous phases have unusual properties that we intend to explore by experimental and theoretical means. Among bulk properties, visco-elasticity and thermal diffusion will be examined. Surface properties are expected to be unusual because of the requirement of the bilayers continuity. We will work with mono-crystals of cubic phases whose sizes can range from millimetre to a fraction of micrometer. Nanoparticles of cubic phases known as cubosomes have been considered for cosmetologic and pharmacologic applications. The experiments will be performed in CNRS, Orsay in the group of Prof. Pieranski who is one of the best experts in this field. The theoretical part will consist of determination and analysis of cubosomes and other structures obtained in experiments. The theoretical calculations and experiment supplement each other perfectly since it is easier to study small structures in theory and large structures in experiments.
A11. Shape transformations of multicomponent biological membranes
Bicontinuous cubic lyotropic phases
Dr hab. Wojciech. T. Gozdz in collaboration with
Prof. Ales Iglic (University of Ljubljana, Slovenia)
Biological membranes are composed of many different constituents such as lipids, proteins and polymers. The components may freely diffuse and under appropriate conditions phase separate. Such processes may lead to many types of shape transformations of the membranes that in turn influence the biological functions. Processes which may be important for functioning of biological cells will be investigated within mesoscopic theory based on the elastic properties of lipid membranes and statistical mechanics of quasi two-dimensional mixture. We will focus on the phase separation of the components and the effect of diffusing macromolecules on the shape transformations of biological cells.
A12. Effect of boundary conditions on self-assembly
Prof. Alina Ciach in collaboration with
Prof. Enrique Lomba (Institute of Physical Chemistry Rocasolano, CSIS, Madrid, Spain)
Prof. Siegfried Dietrich (Max Planck Institute, Stuttgart, Germany)
Prof. Johan S. Hoye (Norwegian University of Science and Technology, Trondheim, Norway)
Systems containing particles self-assembling into micelles, mono- or bilayers or other aggregates will be studied in the framework of statistical mechanics. The analytical, numerical and simulation studies of generic models of such systems will be focused on structural changes that occur in containers one- or two orders of magnitude larger than the equilibrium separation between the aggregates. Effects of stiff walls will be compared with the effects of elastic, deformable walls, such as outer membranes of organella or vesicles. Fundamental studies of the effects of confinement are important for future designing of nano- or micrometer scale compartments or devices possesing complex internal structure.
A13. Effect of ionic solutes on thermodynamic Casimir force
Prof. Alina Ciach in collaboration with
Prof. Siegfried Dietrich (Max Planck Institute, Stuttgart, Germany)
Long-range fluctuations in fluids close to the critical point induce thermodynamic Casimir force between confining surfaces, in particular between surfaces of colloidal particles. Since the critical Casimir forces offer temperature-dependent control over the magnitude and even the sign of the force between colloids, they open novel perspectives for the application of colloids as systems with finely tunable structure. The theory of the thermodynamic Casimir force is restricted to uncharged systems, whereas the surface of the colloidal particle is often charged. The subject of the thesis is development of a Landau-type theory in which the neutralizing charges dissolved in the critical system are taken into account. The effect of the distribution of the charges on the total force between the confining walls will be calculated within various approximate methods. The results will be compared with recent experiments [C Hertlein , L. Helden, A. Gambassi, S. Dietrich & C. Bechinger, Nature, 2008, 451, 172].
B1. Modeling of the electron transport in the surface region of solids
Prof. Aleksander Jablonski in collaboration with
Prof. Sven Tougaard (University of Southern Denmark, Odense, Denmark)
Surface sensitive electron spectroscopies (Auger electron spectroscopy - AES and x-ray photoelectron spectroscopy - XPS) are presently becoming very important tools for studies of processes taking place in the surface region of nanometer thickness. Their high sensitivity is due to small escape depth of electrons emitted from solids. Quantification of electron spectroscopies requires developing a reliable and accurate theoretical model relating the measured emitted electron signal intensity with the composition and structure of the surface region.
B2. SERS and fluorescence studies of molecules in heterogeneous nanoenvironments
Different aspects of electron transport will be approached in this project, in particular calculations of cross sections for elastic and inelastic electron interactions inside a solid. This issue still needs attention, and different aspects of the relevant theory will be addressed in the proposed thesis. Second important aspect of work is associated with simulations of electron trajectories in solids with different structures of the surface region. Finally, experimental procedures should be designed for studies of processes at surfaces (surface segregation, ion bombardments effects, adsorption-desorption phenomena, stoichiometry, chemical state, etc.) These studies will be addressed to solids of current technological interest, e.g. selected semiconductors GaN, ZnO, SiC.
Prof. Jacek Waluk in collaboration with
Prof. Johan Hofkens (KULeuven, Heverlee, Belgium)
Molecules located in the vicinity of metal and/or semiconductor surfaces undergo significant changes in their spectral, photophysical, and chemical properties. In particular, completely different behavior can be observed for the same chromophore/surface pair depending on their distance and mutual orientation. Fluorescence can be enhanced by placing the chromophore in the vicinity of a metal surface, whereas the emission is quenched for molecules located at, or very close to metal surfaces. Not all the factors responsible for these phenomena have been identified and the complete theory is still lacking. The goal of the project is to contribute towards understanding the nature of surface - chromophore interactions. A set of appropriate chromophores will be studied by optical microscopy techniques, including Raman and fluorescence, down to a single molecule level. Of particular interest will be studies of chemical reactivity modified by the proximity of active surfaces.
B3. Structural study of self-assembled and graft monolayers and thin layers of semi-conducting organic molecules
Doc. Dr. hab. Robert Nowakowski in collaboration with
Dr. habilite David Djurado, (Commisariat a l'Energie Atomique, Grenoble, France)
This project concerns investigations performed by means of scanning tunneling microscopy and X-ray scattering methods using both laboratories techniques and synchrotron radiation facilities (reflectivity and grazing incidence scattering). The objective is to get and couple both molecular resolution and statistical information on the morphology and crystalline arrangements of organic systems down to the monolayer scale having high potentiality to be used in molecular/organic electronics applications, photovoltaic devices and catalysis. Therefore the behaviour of naphthalene and perylene based diimides and triarylamine dendrimers will be studied. We expect that structural order/disorder of the deposit depends on the stacking mode generated by the different process of deposition/grafting. This knowledge on the inter-molecular organization is of prime importance in view of better understanding electronic properties of the systems mentioned above.
B4. Catalytic activity of mono- and bimetallic palladium-based nanoparticles supported on metal fluorides
Prof. Zbigniew Karpinski in collaboration with
Prof. Erhard Kemnitz (Humboldt Universitat, Berlin, Germany)
A large variety of toxic and ozone layer-depleting organic wastes are mostly burned and environmentally harmful products are produced. In the perspective of sustainable development, the hydrodechlorination of the chlorine-containing molecules into benign products is very attractive. The goal of this project is to develop more stable, selective and active catalysts for hydrodechlorination of carbon tetrachloride and other chloroalkanes. For this purpose metal (Pt, Pd, Au) based catalysts on nanostructured metal fluorides (e.g. AlF3 and MgF2) will be prepared by sol-gel technology. Special attention will be paid to the methodology of the catalyst preparation. The prepared materials will be characterized at various stages of their biography in order to control all steps of the synthesis. The catalyst performance in the hydrodechlorination process will be studied and compared with the analogous materials manufactured by impregnation of the fluorides. The results should bring about important correlations between the reactivity and the physicochemical properties of catalysts.
B5. Development of molecularly-imprinted-polymer chemosensors for selective determination of biorelevant analytes
Prof. Wlodzimierz Kutner in collaboration with
Prof. Francis D'Souza (Wichita State University, Wichita KS, USA)
Preparation of novel materials capable of mimicking recognition functions of biological systems signifies the most challenging task in design and fabrication of new generation of chemosensors. The aim of the project is to develop novel polymer film materials for surface modification and their further utilization as recognition elements. The molecularly imprinted polymers (MIPs) incorporating well-defined mechanisms of molecular recognition of biorelevant analytes and biogenic amines in particular will be designed and prepared. The redox functional monomers (e.g. thiophene derivatives) will be used to form complexes with the analytes in solutions. Subsequent electrochemical polymerization will yield the analyte-templated MIP thin films. After extraction of the analyte, these films will serve to fabricate chemosensors featuring acoustic, i.e., piezoelectric, electrochemical, surface plasmon resonance, or chemical field effect transistor transduction of the detection signal. These polymer materials will be used as surface modifiers for fabrication of low-cost, selective, and sensitive chemosensors of appreciable limit of detection.
B6. Surfaces modified with directly grown carbon nanotubes as bioelectrocatalytic surfaces
Prof. Marcin Opallo in collaboration with
Prof. Eleanor E.B. Campbell of (Edinburgh University, Edinburgh, UK)
There is increasing interest in using carbon nanotubes (CNTs) as electrode component of sensors and fuel cells. CNTs form an extended conducting network with a very large specific area and their properties can be tuned by chemical functionalisation. This strategy allows for increase the bioelectrocatalytic efficiency of enzyme modified electrodes. In this project, we will focus on CNT functionalised by non-covalent binding following their direct growth. These materials will act as electron shuttle between the enzyme and support. The enzymes allowing for dioxygen reduction and oxidation of a variety of organic compounds will be tested. The effect of functionalisation will be investigated in detail and the comparison with functionalised CNTs immobilised in polymer matrices will be made. The selected electrodes will be tested as biosensing elements and/or electrodes in biofuel cell.
B7. Electrosynthesis of metalic nanomaterials at a three phase junction for biosensing
Prof. Marcin Opallo in collaboration with
Prof. Rabah Boukherroub (Interdisciplinary Research Institute, Lille, France)
By immersion of a solid into two immiscible liquids (i.e. organic and water) three phase junction solid|liquid|liquid is created. This system will be exploited as a reactor for electrogeneration of submicrometer, and hopefully nanometer, sized metallic structures. The aim of the project is to find important factors affecting this process and prepare highly sensitive and chemically stable interfaces for chemical and biological sensing. Typically, the aqueous phase will contain metal ions being a source of metal, whereas the organic phase the supporting electrolyte. By manipulating the phase composition, parameters of the electrode process and boundary geometries stripes, rings and particles of different size will be obtained. The obtained surfaces will be further modified with biological species and applied as sensing materials with electrochemical methods, localised surface plasmon resonance and/or surface-enhanced Raman spectroscopy. Such coupling of biological species onto functionalised metal nanostructures will allow the preparation element of biosensing devices.
B8. Simulation of nanostructured surfaces obtained by passivity and growth
Dr hab. Janusz Stafiej in collaboration with
Dr. Dung di Caprio (CNRS, Paris, France)
The purpose of the project is to develop nanostructured surfaces or nanostructured objects on surfaces by means of surface dissolution. Physicochemical models that describe metal dissolution and passive layer formation in various environments will be developed. Then these models will be reduced to discrete cellular automata approach to perform simulations. Based on the simulation results, the surface morphology will be related to the parameters describing the corroding surface. We expect to find the surface in various morphological regimes and characterize transitions between these regimes. The second challenge is to invent a neural network to analyze the topography of the corroded surface. The network will be taught to distinguish topographies of various model regimes and kinetic parameters, by being exposed to simulation data. Thus prepared network will be used to classify experimental data on surface topography.