Article
Phase transitions in Langmuir monolayer of long chain attached fluorescein studied by second harmonic generation technique
Autor
Gutiérrez, Héctor
Echevarria, Lorenzo
Caetano, Manuel
Institución
Resumen
Optical second harmonic generation (SHG) measurements coupled with -A isotherms have been shown
to be helpful, for the following and comprehension of orientational orders and phase transitions in Langmuir
monolayers. Using the SHG-( -A) measurements, monolayers of 5-hexadecanoylaminofluorescein
on the water surface were examined by monolayer compression. The phase transitions were noticeably
revealed. Dependence of the square root of the intensities polarizations quotient in the molecules
surface density, allowed establishing tilting orientation alignment phases. In addition, change in the
monolayer symmetry C∞v → C2v as it goes through the LE–LC phase transition, was clearly recognized. It
was concluded that a possible change in ˇ is taking place due to aggregate formation.