Graphite dynamic properties

Figure 15. Dynamical properties of oxygen molecules in a complete monolayer on graphite at four temperatures. Part a shows how in-plane reorientations determine the first-rank angular time-correlation-function , where a(t) is the change in in-plane orientation angle in time t, plotted on a logarithmic scale. Part b shows the average in-plane translational displacements d(t) in reduced units, obtained by dividing by o=2.46 A, plotted as a function of time in picoseconds. From Ref. [54], Langmuir 3 (1987) 581-587.

In the recent simulation by Matties and Hentschke [36, 37], the adsorption and melting of benzene on graphite was studied via MD simulations. In addition to determining static properties such as the center of mass density distributions and tilt angles as a function of temperature by obtaining time averages, they were also able to obtain dynamic properties such as the surface diffusion constants in the monolayer and the orientational velocity autocorrelation function (OVAF). 

Dynamical properties of the commensurate and uniaxial incommensurate phases according to the model of Refs. 232, 340, and 342 could also be explored by the molecular dynamics technique used [203, 352]. It is found that in-plane and out-of-plane motions can be analyzed separately for ori-entationally ordered N2 on graphite [203]. The 40-ps simulations below the orientational ordering transition (see Ref. 342) show [203] that the amplitude of reorientation is small and the out-of-plane motion nearly harmonic in both phases, whereas the in-plane motion is more complex, because it is anhar-monic and collective. The out-of-plane motion in the disordered phases is still harmonic, but more strongly damped, and the in-plane dynamics cannot be analyzed any more in terms of a cumulant expansion. Thus, there is little qualitative difference between the reorientational motion observed in the commensurate and uniaxially compressed solids. Only the out-of-plane motion is slightly less damped in the uniaxial phase, and the fluctuations from the planar configuration are more pronounced. 

Kowsika, M. V. S. L. N. and Mantena, P. R. (1996), Optimalpultrusion process conditions for improving the dynamic properties of graphite-epoxy composite beams , Materials Evaluation, 54, 386-392. 

For carbon, for example, a common atomistic potential model is the three-body (Tersoff II) potential model [65]. This model accounts for the relative stability of the bulk crystalline diamond and graphite structures and account well for the basic mechanical and dynamic properties of single-walled C-NTs [66]. In the Tersoff II potential model [65] the energy of each individual carbon atom is taken to be half that of the bonding pair. 

Wilson, W.T. "Effect of Radiation on the Dynamic Mechanical Properties of Epoxy Resins and Graphite Fiber/Epoxy Composites", 1986, Ph.D. Thesis, North Carolina State University, Raleigh, NC. 

The mechanical properties of various types of carbon nanotubes have been extensively studied by both theoretical and experimental studies. In 1993, Overney et al. firstly calculated the rigidity of short SWNTs and the calculated Young s modulus was estimated to be about 1500 GPa, similar to that of graphite (65). Then a range of studies predicted that the Young s modulus of carbon nanotubes was approximately 1 TPa (66). The tensile strength of SWNTs was also estimated from molecular dynamics simulation to be 150 MPa (67). 

J. D. Keenan, J. C. Seferis, and J, T. Quinlivan, J.A.P.S., 24, 2375, (1979) J. D. Keenan, Structure and Dynamic Mechanical Properties of TGDDM-DDS Epoxy, Graphite Fibers and Their Composites, M. S. Thesis, Department of Chemical Engineering, University of Washington, Seattle, Washington (1979). 

Bomchil, G., Harris, N., Leslie, M., et al. (1979). Structure and dynamics of ammonia adsorbed on graphitized carbon black. Part 1. Adsorption isotherms and thermodynamic properties. J. Chem. Soc. Faraday Trans. 1, 75, 1535-41. 

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