@article{51aec372cdfa4d87a68e6d2921d68d29,
title = "Formation of ice nanotube with hydrophobic guests inside carbon nanotube",
abstract = "A composite ice nanotube inside a carbon nanotube has been explored by molecular-dynamics and grand canonical Monte Carlo simulations. It is made from an octagonal ice nanotube whose hollow space contains hydrophobic guest molecules such as neon, argon, and methane. It is shown that the attractive interaction of the guest molecules stabilizes the ice nanotube. The guest occupancy of the hollow space is calculated by the same method as applied to clathrate hydrates.",
author = "Hideki Tanaka and Kenichiro Koga",
note = "Funding Information: This work was supported by grant in aid from JSPS and Ministry of Education in Japan, by Okayama Foundation for Science and Technology, and by NAREGI nanoscience project. The authors are grateful to Professor X. C. Zeng and Professor G. T. Gao. Table I. Lennard-Jones size ( σ ) and energy ( ϵ ) parameters for guest species. Guest σ (nm) ϵ ( kJ mol − 1 ) Argon 0.3405 0.9960 Neon 0.2820 0.3017 Methane 0.3758 1.2355 Table II. Angular order parameter of eight-fold symmetry η after the elapse of time t (ns), and potential energy of system E ( kJ mol − 1 ) in inherent structure. t η E 0.04 0.005 − 49.43 1.6 0.15 − 51.46 8 0.39 − 52.25 28 0.15 − 51.17 100 0.26 − 52.42 172 0.93 − 53.37 250 0.90 − 53.56 Table III. Potential energies of water E w and guest argon E g ( kJ mol − 1 ) at pressure p (MPa) by GCMC simulation. p T = 200 K T = 250 K E w E g E w E g 0.01 − 49.28 − 16.94 − 45.08 − 22.13 0.03 − 49.29 − 16.94 − 45.22 − 21.12 0.1 − 49.29 − 16.91 − 45.10 − 21.83 0.3 − 49.31 − 16.88 − 45.16 − 21.82 1 − 49.31 − 16.87 − 45.12 − 21.78 3 − 49.31 − 16.80 − 47.89 − 16.36 10 − 49.32 − 16.74 − 47.74 − 16.29 30 − 49.31 − 16.70 − 47.78 − 16.22 100 − 49.31 − 16.65 − 47.79 − 16.12 FIG. 1. (Color) Side views of molecular coordinates in MD simulations at t = 0.04 , 28, 100, and 172 ns . FIG. 2. (Color) Top and side views of molecular coordinates of the octagonal ice tubes obtained by GCMC simulations with the following guest species at 200 K : (a) argon with random initial configurations at 50 MPa , (b) argon at 30 MPa , (c) neon at 100 MPa , and (d) methane at 10 MPa . FIG. 3. Occupancy calculated by GCMC simulations (filled circle: T = 200 K ; open circle: T = 250 K ) together with those calculated by the approximate method (solid lines: T = 200 K ; dashed lines: T = 250 K ) of the following guest species: (a) argon, (b) neon, and (c) methane. Occupancy by the alternative way with the short-ranged argon-argon interaction at T = 200 K is also given (dash-dot line). In insets, potential-energy curves are shown (thick line; average over all orientations; thin line; the minimum at the given r ). ",
year = "2005",
month = sep,
day = "1",
doi = "10.1063/1.2031127",
language = "English",
volume = "123",
journal = "Journal of Chemical Physics",
issn = "0021-9606",
publisher = "American Institute of Physics Publising LLC",
number = "9",
}