Orientational relaxation of water trapped inside C60 fullerenes

• Published in: Chemical physics letters Vol. 534; pp. 38 - 42
• Main Author: Bucher, Denis
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-05-2012
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2012.03.025

Computer simulations are conducted to study the rotational motion of a single water molecule encapsulated inside a C60 fullerene at temperatures below the nominal freezing point (273K). The study illustrates the crucial role played by hydrogen bonds in determining H2O dynamical properties and its sensitivity to temperature. [Display omitted]
► Fast orientational relaxation is predicted for a single water trapped inside C60. ► The encapsulated water rotates unhindered at temperatures above 100K. ► The lack of H-bond impacts its entropic contribution and response to temperature.
The synthesis of an endohedral C60 fullerene containing a single trapped H2O molecule was recently achieved [K. Kurotobi and Y. Murata, Science 333 (2011) 613–616]. In this Letter, a computational study is conducted to determine the dynamic properties of the trapped water for a range of temperatures between 50 and 300K. MD and ab initio MD (AIMD) simulations show that, in the absence of hydrogen bonds, the orientational relaxation of H2O inside the fullerene cage is fast and nearly temperature independent. These properties could be exploited in the design of future nanotechnologies.