In the present work, by means of the photopyroelectric calorimetric investigations in liquid crystal/naphtopyran (NP) molecule mixtures, the effect of the photoisomerization of NP by UV light on the critical behavior of specific heat could be studied over the smectic-nematic phase transition. It is shown that the UV light irradiation of the sample can shift the critical exponent from a non-universal value typical of the non-irradiated mixture to one close to that of the 3D-XY universality class, predicted for such a transition. This witnesses the optically triggered reduction of the coupling between the smectic and nematic order parameters responsible for the deviation from the XY-like behavior. A tentative explanation is provided based on the weakening of the order parameter coupling caused by the NP molecules entering the smectic layers following the UV light illumination.

Paoloni, S., Mercuri, F., Zammit, U. (2018). Communication: Optically induced decoupling of the smectic-A and nematic order parameters at the AN phase transition in phototropic liquid crystals. THE JOURNAL OF CHEMICAL PHYSICS, 149(13), 131103 [10.1063/1.5050606].

Communication: Optically induced decoupling of the smectic-A and nematic order parameters at the AN phase transition in phototropic liquid crystals

Paoloni, S.;Mercuri, F.;Zammit, U.
2018-10-01

Abstract

In the present work, by means of the photopyroelectric calorimetric investigations in liquid crystal/naphtopyran (NP) molecule mixtures, the effect of the photoisomerization of NP by UV light on the critical behavior of specific heat could be studied over the smectic-nematic phase transition. It is shown that the UV light irradiation of the sample can shift the critical exponent from a non-universal value typical of the non-irradiated mixture to one close to that of the 3D-XY universality class, predicted for such a transition. This witnesses the optically triggered reduction of the coupling between the smectic and nematic order parameters responsible for the deviation from the XY-like behavior. A tentative explanation is provided based on the weakening of the order parameter coupling caused by the NP molecules entering the smectic layers following the UV light illumination.
Pubblicato
Rilevanza internazionale
Articolo
Esperti anonimi
Settore FIS/01 - Fisica Sperimentale
English
Physics and Astronomy (all); Physical and Theoretical Chemistry
http://scitation.aip.org/content/aip/journal/jcp
Paoloni, S., Mercuri, F., Zammit, U. (2018). Communication: Optically induced decoupling of the smectic-A and nematic order parameters at the AN phase transition in phototropic liquid crystals. THE JOURNAL OF CHEMICAL PHYSICS, 149(13), 131103 [10.1063/1.5050606].
Paoloni, S; Mercuri, F; Zammit, U
Articolo su rivista
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/214129
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 1
  • ???jsp.display-item.citation.isi??? 1
social impact