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Structure, dynamics and thermodynamics of water under nano-confinement

Event Details

Event Dates: 

Thursday, November 8, 2012 - 5:00am

Speaker Name(s): 

Prabal Maiti

Speaker Affiliation(s): 

CU Boulder/Indian Institute of Science
Seminar Type/Subject

Event Details & Abstract: 

We study the various translational and orientational dynamics of water molecules confined inside carbon nanotube using atomistic Molecular dynamics simulation (MD). The water molecules inside the nanotube show solid-like ordering at room temperature and surprisingly exhibit Fickian diffusion instead of single-file even if the particles can not cross one another. We propose model systems where single-file diffusion can be observed and test the prediction doing simulation in a nanoring. The confinement leads to strong anisotropy in the reorientational relaxation of the confined water molecules. The time scale of therelaxation of the dipolar correlations become ultra-slow. In contrast, the relaxation of the vector that joins the two hydrogens in a molecule becomes much faster. We also give the thermodynamics of water entry inside hydrophobic nanotube by calculating the Helmholtz free energy of water using two-phase thermodynamic (2PT) method.