Pierre Beaujean

Pierre Beaujean
University of Namur | FUNDP · Department of Chemistry

PhD student

About

14
Publications
1,370
Reads
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160
Citations
Introduction
I'm a Ph.D. student (in the field of quantum chemistry, more specifically nonlinear optics) and Professor's assistant in the laboratory of Professor Benoît Champagne, in the University of Namur (in Belgium) where I also start a bachelor in Computer Science. My Ph.D. thesis focuses on the evaluation of the nonlinear optical response of molecules or systems in gas or condensed phase. It includes computations at the Hartree-Fock, DFT or Coupled Cluster levels for the evaluation of the different contributions. The theoretical works is carried out in close collaboration with experimental characterizations, through our collaborators or the literature.
Additional affiliations
September 2021 - September 2022
University of Namur
Position
  • Research Assistant
September 2015 - September 2021
University of Namur
Position
  • Research Assistant
Education
September 2015 - October 2021
University of Namur
Field of study
  • Chemistry
September 2013 - June 2015
University of Namur
Field of study
  • Chemistry
September 2009 - September 2013
University of Namur
Field of study
  • Chemistry

Publications

Publications (14)
Article
Full-text available
This contribution employs quantum chemistry methods to describe the variations of the second nonlinear optical responses of molecular switches based on benzazolo-oxazolidine (BOX) units, connected by π-linkers, along their successive opening/closing. Under the fully closed forms, all of them display negligible first hyperpolarizability (β) values....
Article
The elaboration of multichromophoric system which can undergo a reversible transformation over more than two different states can be easily performed by the covalent assembly of several identical switching subunits around a central node. However, the selective addressability of each of them still represents a challenging task. This study reports on...
Article
Owing to their intense emission, low toxicity and solubility in aqueous medium, fluorescent organic nanoparticles (FONs) have emerged as promising alternatives to inorganic ones for the realization of exogenous probes for bioimaging applications. However, the intimate structure of FONs in solution, as well as the role played by intermolecular inter...
Article
Molecular switches are chemical compounds exhibiting the possibility of reversible transformations between their different forms accompanied by a modification in their properties. Among these, switching of multi-addressable Benzazolo-OXazolidines (BOXs) from a closed form to an open form results in drastic modifications in their linear and nonlinea...
Article
The second-order nonlinear optical responses of a series of recently designed dipolar merocya- nines are investigated using the 2006 Minnesota family of hybrid exchange-correlation functionals (XCFs), as well as the LC-BLYP, ωB97XD and CAM-B3LYP long-range (LR) corrected XCFs. The performance of these different levels of approximation is discussed...
Article
The vibrational contributions to the average polarizability, to the second harmonic scattering (SHS) first hyperpolarizability, and depolarization ratio, as well as to the third harmonic scattering (THS) second hyperpolarizability and depolarization ratio, have been evaluated for the water molecule using the Bishop and Kirtman perturbative theory a...
Chapter
This chapter addresses the methodological and computational aspects related to the prediction of molecular second-order nonlinear optical properties, i.e., the first hyperpolarizability (β), by using quantum chemistry methods. Both small (reference) molecules and extended push-pull π-conjugated systems are considered, highlighting contrasted effect...
Article
Full-text available
The static and dynamic second harmonic (\(\beta _{\mathrm{SHS}}\)) and third harmonic (\(\gamma _{\mathrm{THS}}\)) scattering hyperpolarizabilities and depolarization ratios of water, carbon tetrachloride, chloroform, dichloromethane, chloromethane, and acetonitrile have been evaluated at the coupled cluster response theory level of approximation....
Article
Full-text available
The static and dynamic first (β ‖) and second (γ ‖) hyperpolarizabilities of water, methanol, and dimethyl ether have been evaluated within the response function approach using a hierarchy of coupled cluster levels of approximation and doubly augmented correlation consistent atomic basis sets. For the three compounds, the electronic β ‖ and γ ‖ val...
Article
A combined experimental-theoretical investigation has revealed that oxazine-based compounds are multi-addressable, multi-state, and multi-functional molecular switches exhibiting contrasts of both linear and second-order nonlinear optical properties. The switching properties are particularly large when the substituent is a donor group. In this stud...
Chapter
In an attempt to design molecular electromechanical actuators with large deformation response, we present here three helicene–like compounds, which offer signifi cant strain above 5 % due to two–electron charge transfer (CT). The shrinking induced by CT is a quantum mechanical orbital effect. A good π–π overlap across the helical pitch is critical...
Article
Full-text available
In an attempt to design molecular electromechanical actuators with large deformation response, we present here three helicene-like compounds, which offer significant strain above 5 % due to two-electron charge transfer (CT). The shrinking induced by CT is a quantum mechanical orbital effect. A good π–π overlap across the helical pitch is critical f...

Projects

Project (1)
Project
This project aims at investigating nonlinear optical properties of various fluorescent proteins for applications in second-harmonic and two-photon excitation microscopies by the simplified time-dependent functional theory (sTD-DFT) method. The main practical goal is to improve the dyes brightness by fine-tuning their protein cavity. This is particularly important because lower intensity laser light sources can reduce phototoxicity problems. For this purpose, new theoretical tools will be developed within the sTD-DFT framework, including a widely applicable multipole scheme and a general (basis set) tight-binding (gTB) method for large systems.