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Reference : UMR8000-SERDEN-002
Workplace : ORSAY
Date of publication : Friday, April 30, 2021
Scientific Responsible name : DENISOV Sergey
Type of Contract : PhD Student contract / Thesis offer
Contract Period : 36 months
Start date of the thesis : 1 October 2021
Proportion of work : Full time
Remuneration : 2 135,00 € gross monthly
Description of the thesis topic
The post is created as part of the project ANR RAD3P (https://elyse-platform.academy/projects/)
The objective of the Rad3P project aims to study for the first time the evolution of excited states of transient anion radicals of DNA/peptides models (quantum efficiencies of state-to-state transition) in an aqueous solution. Excited-state chemistry of anion radicals is important in the light of dissociative electron attachment (DEA) since it could play role in the reductive damage path for DNA/peptides through the formation of the excited anion radicals undergoing irreversible dissociation. In the course of the project Rad3P, unique radiolysis spectroscopy will be developed based on “Pump-Repump-Probe” spectroscopy approach, by replacing the Pump with an electron Pulse, which was never performed in radiation studies.
The “Pump(electron pulse)-Repump(laser)-Probe(supercontinuum)” spectroscopy consists of reexciting solute anion radicals formed in reaction with descendants of secondary electrons: presolvated and solvated by a short (100 fs) optical pump (variable energy). The fate of excited anion radicals could be then studied with a proper time resolution with a third spectrally broad 100 fs probe pulse, namely following bleaching of ground-state absorption of the radical anion and the dynamics of excited-state evolution.
The newly generated knowledge will have great importance to radiotherapy techniques fighting cancer, to the codes devoted to the modeling of ionization radiation interaction with matter, DNA/peptide damage which ignores DEA at the moment. In addition, the project addresses both technological and scientific challenges by developing new spectroscopy extending the applicability of the pulse radiolysis technique. It will provide a new way for research under ionization radiation since it is clear that there is plenty of room in the short timescale. During this project, we will also implement a data management plan to give access to the community the generated experimental data.
The candidate will work on the ELYSE platform, built around a picosecond electron accelerator (University of Paris Saclay, France, Orsay) under the supervision of Dr. DENISOV Sergey (https://elyse-platform.academy/dr-denisov-sergey-a/). The platform is a part of the CNRS Institute of Chemical Physics UMR8000.
Along with the progress of the work, two goals major will be achieved:
1) Electron Pulse-Repump-Prove spectroscopy will be developed.
2) The time-resolved behavior of transient states of DNA base anion radicals will be studied.
The candidate will need to deal with the development of the time-resolved spectroscopy, including software development for its control. The candidate will conduct experiments, do data analysis, do bibliographic research, learn how to write manuscripts of research articles.
PhD student will develop research skills in modern time-resolved spectroscopy, radical chemistry, photophysics of molecules, accelerator physics, software development.
Constraints and risks
The professional risks will be related to working with UV-Vis laser radiation; the chemical risks will also be applicable to a much smaller extent.
The candidate must have a solid background in physics and physical chemistry, a good knowledge of chemistry basics, basic knowledge of any modern computer programming languages, e.g., Python, Java, etc.
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