Strongly anisotropic orientational relaxation of water molecules in narrow carbon nanotubes and nanorings.
Molecular dynamics simulations of the orientational dynamics of water molecules confined in narrow carbon nanotubes and nanorings reveal that confinement leads to strong anisotropy in the orientational relaxation. The relaxation of the aligned dipole moments, occurring on a time scale of nanoseconds, is 3 orders of magnitude slower than that of bulk water. In contrast, the relaxation of the vector joining the two hydrogens is ten times faster compared to bulk, with a time scale of about 150 fs. The slow dipolar relaxation is mediated by the hopping of orientational defects, which are nucleated by the water molecules outside the tube, across the linear water chain.
Mukherjee
Biswaroop
B
Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
Maiti
Prabal K
PK
Dasgupta
Chandan
C
Sood
Ajay K
AK
D016880:Anisotropy; D003198:Computer Simulation; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods; D037742:Nanotubes, Carbon / Q000737:chemistry*; D010316:Particle Size; D016062:Porosity; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
D046911:Macromolecular Substances; D037742:Nanotubes, Carbon; D014867:Water