Seminars are are currently organized by Dott. Lara Querciagrossa and Dr. Luca Muccioli .

Seminars are held (except when explicitly indicated otherwise) in Biblioteca di Chimica Fisica, Dipartimento di Chimica Fisica ed Inorganica, Viale Risorgimento,4, Bologna. Everybody welcome!


 

13 September 2011 at 14.30, Biblioteca Chimica Fisica

Dr. Hitomi Nomura
Koda Lab, Graduate School of Science and Engineering
Yamagata University, JAPAN

“Computing Chemical Potential using the Phase Space Multihistogram
Method”

We present a new simulation method to calculate the free energy and the chemical potential of hard particle systems. The method relies on the introduction of a parameter dependent potential to smoothly transform between the hard particle system and the corresponding ideal gas. We applied the method to study the phase transition behavior of monodispersed infinitely thin square platelets. First, we equilibrated the square platelet system for different reduced pressures with a usual isobaric Monte Carlo (MC) simulation and obtained a reduced pressure-chemical potential plot. Then we introduce the parametrized potential to interpolate the system between theideal gas and the hard particles. After selecting the potential, we performed isochoric MC runs, ranging from the ideal gas to the hard particle limit.Through an iterative procedure, we compute the free energy and the chemical potential of the square platelet system by evaluating the volume of the phase space attributed to the hard particles, and then we find the coexistence pressure of the system. Our method provides an intuitive approach to investigate the phase transitions of hard particle systems.

Reference:
Hitomi Nomura, Tomonori Koda, Akihiro Nishioka, Ken Miyata, Computing Chemical Potential using the Phase Space Multi-histogram Method
submitted


 

 
 

The presentation focuses on the fabrication of nano-structures using lyotropic liquid crystals with discotic shaped molecules in which the orientation of the grapheme layers can be manipulated using surface anchoring techniques. It will also be shown how to create patterned arrays of nanotubes using a pen writable technique and some of the work at Brown University on continuous surface boundary conditions created through a holographic exposure process of linear photopolymerizable polymer (LPP) alignment layers.

 

(ii) the phenomenological Landau-de Gennes theory.

The first approach shows the existence of a weak subsurface deformation, while the anchoring strength resulting from the model is rather large.
The second approach, on the other hand, shows that a localized subsurface variation of the scalar order parameter can also induce a subsurface deformation and can result in an additional intrinsic contribution to the effective anchoring.

 


page last updated September 2011 (CZ)