The use of local Cross-Polarization NMR methods in the study of molecular dynamics in organic solids

• Grant number: 07/08346-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: March 01, 2008
• End date: November 30, 2008
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Eduardo Ribeiro de Azevedo
• Grantee: Márcio Fernando Cobo
• Host Institution: Instituto de Física de São Carlos (IFSC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

The aim of this project is to show the viability of using NMR local Cross-Polarization (usually known as LG-CP) for detailed characterization of molecular motions in organic solids. Specifically, we intend to use the LG-CP method for characterizing amplitudes, correlation times, and the activation energies of molecular motions occurring with correlation times in the miliseconds to microseconds range (usually known as intermediate motional regime). These methods were already applied in our laboratory, but only in a semi-quantitative way. Therefore, in this project the student will evaluate the viability of using such methods for obtaining quantitative information about the motions. To achieve that he will perform experiments in model systems with known dynamics and compare the results with numerical simulations (carried-out with a spin dynamics simulation program that take into account the effect of the molecular motion in the evolution of the nuclear spins). Besides that, the method will also be used for the characterization of the molecular dynamic processes responsible by the beta relaxation of two electroluminescent polymers. (AU)