Aliaksandra Lisouskaya

Belarusian State University, Minsk, Belarus, M.Sc. Chem.(2009), Ph.D.(2012)

Phone: (574) 631-5457
Email: alisousk@nd.edu
Office: 105C Radiation Research Building

Radiation Chemistry and Photochemistry in Aqueous Solutions

Scientific Interests

Pulse Radiolysis of Aqueous Media

Kinetics and mechanisms of radical reactions of nuclear reactor water under high temperatures and pressures. Pulse radiolysis of transition metal ions over wide temperature ranges to solve radiolytic corrosion problems for both current and future generation reactors.

Radiation Chemical Impacts on the Nuclear Waste Stream

Radiolytic stability of solvents and organic ligands used in separation systems in nuclear waste reprocessing. Time resolved EPR spectroscopic techniques to establish identity and kinetics of transients from organic ligands used in solvent extraction processes.

Free Radical and Redox Chemistry of Bioorganic Compounds

Mechanisms of free radical reactions of organic compounds and biomolecules probed by pulse radiolysis, flash photolysis and EPR spectroscopy that have applications ranging from those relevant to the nuclear power industry to photochemistry of importance in biology and medicine.

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Recent Accomplishments

Reaction kinetics of Ni^2+/+ ions and spectral changes in Ni⁺ absorbance under critical conditions of temperature and pressure are revealed by pulse radiolysis. We found that the absorption spectrum of short-lived monovalent nickel ion shifts to shorter wavelength with increasing temperature. This phenomenon might be explained by a decrease in the average number of water molecules coordinated to the metal in the first solvation shell. To obtain the reaction constants, we performed extensive experiments and further fitting of the Ni⁺ kinetics in various salt and pH solutions. All measured rate constants followed approximate Arrhenius behavior. These new data on the reactivity of nickel ions dissolved in water upon irradiation at high temperatures and pressures is key for understanding future studies of the effect of Ni^2+/+ on the bulk coolant radiolysis chemistry under typical pressurized and boiling water reactors (PWR/BWR) conditions.

 

Radicals from tributyl phosphate decomposition: a combined electron paramagnetic resonance spectroscopic and computational chemistry investigation 

This study presents experimental data obtained by the methods of electron paramagnetic spectroscopy and computational chemistry for studying the structure of radicals derived from tributyl phosphate (TBP) under irradiation. TBP is exposed to high doses of ionizing radiation during nuclear waste separation and it is necessary to understand its radiolytic degradation pathways. We applied spin-trapped EPR to estimate radiation-chemical yields of TBP radicals formed in situ under X-ray irradiation at room temperature. To find the structure of radicals formed from TBP, we use low-temperature EPR. To study the reactions of TBP with the OH radical in aqueous solutions, we used the continuous flow EPR method at room temperature, which also makes it possible to elucidate the radical kinetics. An automatic conformational analysis on TBP-derived radicals was performed to investigate the possible radical conformations. The obtained data make it possible to estimate the radiation resistance and determine the structure of radical conformers induced by irradiation with X-rays or electron beams, and chemically generated.

Unveiling the mechanism of photodamage to sphingolipid molecules via laser flash photolysis and EPR

The work reported here is designed to uncover details of the mechanism of damage to such lipids by UV radiation. Our approach employs laser flash photolysis and EPR spectrometry to explore the mechanism of the decay reactions, and to determine the associated kinetic parameters. To interpret our experiments, we computed both excitation energies and EPR parameters of radicals formed during photolysis. Employing the spin-trap EPR method confirmed the formation of both carbon- and nitrogen-centered radicals. Thus, we can conclude that the photodecomposition of sphingolipids and their analogues proceeds by Norrish type I reactions with the formation of both nitrogen-centered and alkyl radicals. These data provide insights for the development of UV-protective approaches based on a detailed understanding of molecular events that occur in the skin lipids after UV exposure.

 

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Selected Publications

Sosulin I.S., D.H. Ryan, A. Lisouskaya. "Radicals from Tributyl Phosphate Decomposition: a Combined Electron Paramagnetic Resonance Spectroscopic and Computational Chemistry Investigation" Phys. Chem. Chem. Phys. (2023)

Lisouskaya A., U. Markad, D.M. Bartels. "Reactions of Nickel Ions in Water Radiolysis up to 300 °C." J. Phys. Chem. B, 127 (2023) 2784–91.

Lisovskaya A., O. Schiemann, I. Carmichael. "Unveiling the Mechanism of Photodamage to Sphingolipid Molecules via Laser Flash Photolysis and EPR" Photochemistry and Photobiology (2023)

Lisouskaya A., U. Markad, I. Carmichael, D.M. Bartels "Reactivity of Zn+aq in High-Temperature Water Radiolysis" Phys. Chem. Chem. Phys. 24 (2022) 19882–9.

Lisouskaya, A., P. Tarábek, D.M. Bartels, I. Carmichael "Persistent Radicals in Irradiated Imidazolium Ionic Liquids Probed by EPR Spectroscopy" Rad. Phys. Chem. 202 (2022) 110513.

Lisovskaya A., I. Carmichael, A. Harriman. (2021) "A Pulse Radiolysis Investigation of Radicals Derived from Water-Soluble Cyanine Dyes: Implications for Super-Resolution Microscopy" J. Phys. Chem. A, 125 (2021), 5779–93.

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