کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
444318 692967 2012 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Phase transition study of confined water molecules inside carbon nanotubes: Hierarchical multiscale method from molecular dynamics simulation to ab initio calculation
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
Phase transition study of confined water molecules inside carbon nanotubes: Hierarchical multiscale method from molecular dynamics simulation to ab initio calculation
چکیده انگلیسی

In this study, the mechanism of the temperature-dependent phase transition of confined water inside a (9,9) single-walled carbon nanotube (SWCNT) was studied using the hierarchical multi-scale modeling techniques of molecular dynamics (MD) and density functional theory (DFT).The MD calculations verify the formation of hexagonal ice nanotubes at the phase transition temperature Tc = 275 K by a sharp change in the location of the oxygen atoms inside the SWCNT. Natural bond orbital (NBO) analysis provides evidence of considerable intermolecular charge transfer during the phase transition and verifies that the ice nanotube contains two different forms of hydrogen bonding due to confinement. Nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) analyses were used to demonstrate the fundamental influence of intermolecular hydrogen bonding interactions on the formation and electronic structure of ice nanotubes. In addition, the NQR analysis revealed that the rearrangement of nano-confined water molecules during the phase transition could be detected directly by the orientation of 17O atom EFG tensor components related to the molecular frame axes. The effects of nanoscale confinements in ice nanotubes and water clusters were analyzed by experimentally observable NMR and NQR parameters. These findings showed a close relationship between the phase behavior and orientation of the electronic structure in nanoscale structures and demonstrate the usefulness of NBO and NQR parameters for detecting phase transition phenomena in nanoscale confining environments.

Figure optionsDownload high-quality image (203 K)Download as PowerPoint slideHighlights
► Phase transition of water inside a SWCNT is modeled by multi-scale methods.
► The phase behavior of confined water could be traced via NBO, NMR and NQR methods.
► Confinement makes the electronic structure of ice nanotube different from ice Ih.
► Two forms of H-bonding due to confinement are clarified in ice nanotube.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Graphics and Modelling - Volume 38, September 2012, Pages 40–49
نویسندگان
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