Characterization of the second-order nonlinear optical properties of oxazine molecular switches by quantum chemistry calculation and hyper-Rayleigh scattering spectroscopy

Student thesis: Master typesMaster in Chemistry

Abstract

Some compounds show large variation of structures in response to an external stimulus. This ability can be exploited to create switches with controllables and predictibles properties. They generally possess two forms : on (large value of a given property) and off (small value). One try to get a large contrast between these two forms. The prediction of their property is an important part of their design.

The goal of this master thesis is to study the benzo[1,3]oxazine/indolinium familly for their application as second-order nonlinear optical switches (which present a variation of their first hyperpolarizability) by using a multidisciplinar approach : experimental characterizations by HRS spectroscopy and quantum chemistry calculations. Triggering from closed (off) to open (on) form can be performed using irradiation by light or acidic conditions. Those molecules can also be substituted on the 2 position of indole, and the effects of different substituants on the first hyperpolarizability were highligted.

Particularly, donor substituents (with a large π-conjugated path) improve the contrast ratio between open and closed forms, which is not the case with acceptor substituents. The opening reaction also plays an important role in the open form response. To obtain such results, several approaches have been used: Hartree-Fock level calculations and inclusion of electron correlation at the MP2 level. Comparison between between both theoretical and experimental results is performed using a model to avoid the resonance effects. Correlation between calculation and experiment is good.
Date of Award22 Jan 2015
Original languageEnglish
Awarding Institution
  • University of Namur
SupervisorBenoît Champagne (Supervisor) & Aurélie Plaquet (Co-Supervisor)

Cite this

Characterization of the second-order nonlinear optical properties of oxazine molecular switches by quantum chemistry calculation and hyper-Rayleigh scattering spectroscopy
Beaujean, P. (Author). 22 Jan 2015

Student thesis: Master typesMaster in Chemistry