Organizing co mmittee

PRENUCLEATION CLUSTERS OF FLAT PERYLENE MOLECULES 
 
D. Husanova
1
, J. Ochilov
1,2
, U. Khalilov
1,3 
 
1) Laboratory of Thermal Physics of Multiphase Systems, Arifov Institute of Ion-Plasma 
and Laser Technologies, Academy of Sciences of Uzbekistan, Durmon yuli str, 33, 
100125, Tashkent, Uzbekistan, 
e-mail: [e-mail]
, 
2) National University of Uzbekistan named after Mirzo Ulugbek University str. 4, 
100174, Tashkent, Uzbekistan, 
e-mail: [e-mail]
, 
3) Research Group PLASMANT, NANOLabCenter of Excellence, Department of 
Chemistry, University of Antwerp, Universiteitsplein 1, 2610, Antwerp, Belgium,
e-mail: [e-mail] 
 
In spite of tremendous efforts, the pre-nucleation processes of organic nanocrystals 
(ONC) are still difficult to understand. This study investigates the formation processes 
of pre-nucleated clusters of three flat perylene (PERLEN08 - C
20
H
14
, WUFJEM - 
C
21
H
14
O and RELVUC - C
22
H
24
O
2
) molecules using reactive molecular dynamics (MD) 
simulations. The results show that two dimer structures, i.e., “face-to-face” and “face-
to-edge” molecular structures were formed in the first stage of the accumulation of flat 
perylene (C
20
H
12
, C
21
H
14
O and C
22
H
24
O
2
) molecules in a vacuum. In particular, in the 
case of PERLEN08 clustering, the molecules combine based on face-to-face and later 
face-to-edge (T-shaped) positions, while in the cases of WUFJEM and RELVUC, 
molecules combine in a more face-to-face (parallel) position due to hydrogen bonding. 
In addition, due to the number of hydrogen bonding, the degree of clustering of 
RELVUC molecules is higher than that of WUFJEM molecules. Subsequently, dimers 
gradually convert to trimers, tetramers and finally a cluster (Fig. 1). During the 
simulation, clusters aggregate to form a bigger amorphous structure, which eventually 
leads to the formation of a crystal nucleus. Such onset of
crystal nucleation can be 
explained by the non-classical nucleation theory. In overall, the obtained results help to 
understand the mechanisms of the first steps of growth of organic nanocrystals based on 
different type of flat perylene molecules in a vacuum environment. 
Fig. 1. (a) The evolution of the cluster formation of flat perylene molecules.
(b) Cluster formation time as a function of molecule types.