Home Todos os Eventos Details - Dora Izzo (UFRJ): A full mean field description of the nematic to smectic phase transitions

EMail Print

Todos os Eventos

Event 

Title:
Dora Izzo (UFRJ): A full mean field description of the nematic to smectic phase transitions
When:
01.12.2014 11.00 h
Where:
Sala A5-01 - Niteroi
Category:
Seminários

Description

Seminário de Mecânica Estatística

 

Convidamos a todos para o seminário de Mecânica Estatística
que será apresentado na próxima segunda-feira, 1/12/2014, às 11:00h, na sala A5-01 do Instituto de Física.

Título: A full mean field description of the nematic to smectic phase transitions

Apresentador: Dora Izzo – Instituto de Física da UFRJ

Resumo: Recent experiments on thermotropic liquid crystals have shown the occurrence of an additional phase transition: the biaxial nematic to smectic-C phase transition. This possibility has not been predicted by theory yet. We consider the traditional model, where the ordering in the liquid crystal is described by a tensorial order parameter associated to the molecule quadrupole moment. The phase behavior of the system is obtained using a mean field approach: we use Landau-de Gennes theory. The free energy is an expansion in terms of the invariants associated to tensorial order parameter. Our study resembles that of Galerne and Marcerou(1) for the nematic phases in a lyotropic liquid crystal. The equations obtained from the mean field theory were minimized analitically leading to closed expressions for the invariants. Nevertheless, to compare the free energies of the different phases, we had to rely on numerical computations. A rich phase diagram was obtained. We observe the occurrence of all phases observed traditionally: isotropic, uniaxial nematic, biaxial nematic, smectic phases of two types, but the novelty is the possibility of the biaxial nematic to smectic transitions.
(1) Y.Galerne and J.P.Marcerou, J. Physique 46,589-594 (1985).

Venue

Group:
Sala A5-01
Street:
Instituto de Física da UFF
ZIP:
24210-346
City:
Niteroi
State:
RJ
Country:
Country: br

Description

Sorry, no description available
<<  Jul 20  >>
 Su  Mo  Tu  We  Th  Fr  Sa 
     1  2  3  4
  5  6  7  8  91011
12131518
192225
2629