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In gas phase it is known that two particles with same sign of charges repel each other. However,
in condensed phase in a system with a large number of charges, interaction between two like
charges may differ from the gas phase scenario [1, 2]. In some cases the two like charges may
even attract each other. It can be a reason for phenomena such as aggregation of macroions,
fusion of lipid vesicles, DNA condensation, and formation of Actin filament in a biological cell.
However, the underlying reasons for this attraction are still not clear. Various proposals have
been put forward in last three decades such as charge inversion, counterion charge density
waves, Coulomb depletion etc. This is still one of the fundamental problems in electrostatics yet
to be understood completely.
In the current talk, at first a historical description of treating a system with multiple ions will be
given starting from the celebrated Debye-Huckel theory. Then our preliminary investigations
will be given both for spherical systems and proteins. Using both molecular simulations and
liquid state integral equation theories we could rationalize some of the experimental findings for
the systems considered.
Reference:
(1) Like-charge attraction between polyelectrolytes induced by counterion charge density waves
T. E. Angelini, H. Liang, W. Wriggers, and G. C. L. Wong PNAS (2003).
(2) Attractive Forces between Charged Colloidal Particles Induced by Multivalent Ions Revealed
by Confronting Aggregation and Direct Force Measurements
P. Sinha, I. Szilagyi, F. J. Montes Ruiz-Cabello, P. Maroni, and M. Borkovec, JPC Letters
(2013). |