ETD

Archivio digitale delle tesi discusse presso l'Università di Pisa

Tesi etd-10192003-214820


Tipo di tesi
Tesi di laurea vecchio ordinamento
Autore
Bizzarri, Marco
Indirizzo email
marco78zz@virgilio.it
URN
etd-10192003-214820
Titolo
Simulazione di trasformazioni di fase e dinamica del 4-pentil-4'-cianobifenile (5CB)con potenziale derivato da calcolo ab-initio
Dipartimento
SCIENZE MATEMATICHE, FISICHE E NATURALI
Corso di studi
CHIMICA
Relatori
relatore Tani, Alessandro
Parole chiave
  • Nessuna parola chiave trovata
Data inizio appello
19/11/2003
Consultabilità
Non consultabile
Data di rilascio
19/11/2043
Riassunto
In this work, an intermolecular potential for the interaction between 5CB pairs has been reconstructed from a database of interaction energies of the molecular fragments, calculated
from ab-initio methods at MP2 level. This function has been employed in a series of molecular dynamics simulations at various temperatures. The simulation results show the experimental cristalline structure stays kinetically stable throughout the temperature range of experimental cristalline phase. We also found a nematic phase at higher temperature and an isotropic liquid phase at still higher temperature. The various phase have been characterized from a structural
( radial distribution functions and conformational
distribution function of the chain )and dynamic ( diffusion coefficient ) point of view. In the case of nematic phase we have calculated total
and local orientational order parameters to compare to the data obtained from NMR
spectroscopy while translational diffusion has been studied for both longitudinal ( i.e. along the director ) and both transverse motions.
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