# C60

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

  200 lightgrey C60.pdb  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

## Gel phase

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