C60

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C60, also known as Buckminsterfullerene is composed of carbon atoms.


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C60

Models

Girifalco potential

The Girifalco intermolecular pair potential is given by [1] (Eq. 4):

\Phi (r) = -\alpha \left[ \frac{1}{s(s-1)^3}+ \frac{1}{s(s+1)^3}- \frac{2}{s^4}\right] + \beta \left[ \frac{1}{s(s-1)^9}+ \frac{1}{s(s+1)^9}- \frac{2}{s^{10}}\right]

where

s=\frac{r}{2a}
\alpha = \frac{N^2A}{12(2a)^6}
\beta = \frac{N^2B}{90(2a)^{12}}

where N is the number of atoms on each sphere, i.e. N=60.

Approximate non-conformal potential

The Approximate non-conformal potential (ANC) for the C60 fullerene is given by (Eq 6 in [2]):

\Phi_{12}(z) =  \epsilon \left[ \frac{1-a}{(z^3/S +1 - 1/S)^{1/3} -a} \right]^{12} - 2\epsilon \left[ \frac{1-a}{(z^3/S +1 - 1/S)^{1/3} -a} \right]^{6}

where

  • z := r/r_m
  • r_m = 1.0281 nm
  •  a = 0.09574 is the hard-core diameter in units of r_m
  •  \epsilon = 3297.28 K is the well depth
  • S = 0.4120 is a softness parameter

Phase diagram

[3] [4] [5] [6]

Liquid phase

[7]

Gel phase

Simulations of the Girifalco potential indicate a possible gel composed solely of C60 molecules [8]

References

Related reading