Ultrafast optical spectroscopy applied to photochemical reactions and biological processes

• Grant number: 11/06978-7
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Start date: October 01, 2011
• End date: February 29, 2012
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Cleber Renato Mendonça
• Grantee: Ismael Andre Heisler
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

This document describes a proposal for a postdoctoral fellowship application. The general objective to be addressed by the proposal is the implementation of ultrafast optical spectroscopy techniques at the Grupo de Fotônica do IFSC-USP, which will be used for femtochemistry research.The two main research subjects will be centred on the study of photoisomerisation reactions in azocompounds and charge transfer reactions in triarylamine based molecules. These are femtochemistry reactions because their dynamics develops on ultrafast timescales. Both reactions are of fundamental importance in chemistry and biology. The techniques to be implemented are upconversion time resolved fluorescence and transient absorption spectroscopy, which will have sub 200 fs time resolutions. The objective is to capture the photoisomerisation dynamical development along the reaction coordinate and describe the relaxation mechanisms and timescales as well as its connections to macroscopic quantities like viscosity and polarity. Also, the ultrafast spectroscopy measurement results will be used to create a kinetics scheme which will describe the excited state dynamics underlying charge transfer reactions. Other measurements and theoretical modelling with appropriate models will provide additional information. Ultimately this information can be used to create and describe the energy potential surface as a function of the reaction coordinate for the femtochemistry reactions being studied. (AU)