ExpandedMie

class hoomd.md.pair.ExpandedMie(nlist, default_r_cut=None, default_r_on=0.0, mode='none')

Bases: Pair

Expanded Mie pair force.

Parameters:

• nlist (hoomd.md.nlist.NeighborList) – Neighbor list.

• default_r_cut (float) – Default cutoff radius $[\mathrm{length}]$.

• default_r_on (float) – Default turn-on radius $[\mathrm{length}]$.

• mode (str) – Energy shifting/smoothing mode.

ExpandedMie computes the radially shifted Mie pair force on every particle in the simulation state:

$$U(r) = \left( \frac{n}{n-m} \right) {\left( \frac{n}{m} \right)}^{\frac{m}{n-m}} \varepsilon \left[ \left( \frac{\sigma}{r-\Delta} \right)^{n} - \left( \frac {\sigma}{r-\Delta} \right)^{m} \right]$$

Example:

nl = nlist.Cell()
expanded_mie = pair.ExpandedMie(nlist=nl, default_r_cut=3.0)
mie.params[("A", "B")] = {
    "epsilon": 1.0,
    "sigma": 1.0,
    "n": 12,
    "m": 6,
    "delta": 0.5,
}
expanded_mie.r_cut[("A", "B")] = 2 ** (1.0 / 6.0)
expanded_mie.params[(["A", "B"], ["C", "D"])] = {
    "epsilon": 1.5,
    "sigma": 2.0,
    "n": 12,
    "m": 6,
    "delta": 0.5,
}

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Members inherited from AutotunedObject:

property kernel_parameters

Kernel parameters. Read more...

property is_tuning_complete

Check if kernel parameter tuning is complete. Read more...

tune_kernel_parameters()

Start tuning kernel parameters. Read more...

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Members inherited from Force:

additional_energy

Additional energy term. Read more...

additional_virial

Additional virial tensor term $W_\mathrm{additional}$. Read more...

cpu_local_force_arrays

Local force arrays on the CPU. Read more...

energies

Energy contribution $U_i$ from each particle. Read more...

energy

The potential energy $U$ of the system from this force. Read more...

forces

The force $\vec{F}_i$ applied to each particle. Read more...

gpu_local_force_arrays

Local force arrays on the GPU. Read more...

torques

The torque $\vec{\tau}_i$ applied to each particle. Read more...

virials

Virial tensor contribution $W_i$ from each particle. Read more...

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Members inherited from Pair:

nlist

Neighbor list used to compute the pair force. Read more...

mode

Energy smoothing/cutoff mode. Read more...

r_cut

Cuttoff radius beyond which the energy and force are 0. Read more...

r_on

Radius at which the XPLOR smoothing function starts. Read more...

compute_energy()

Compute the energy between two sets of particles. Read more...

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Members defined in ExpandedMie:

params

The Expanded Mie potential parameters. The dictionary has the following keys:

• epsilon (float, required) - $\epsilon$ $[\mathrm{energy}]$.

• sigma (float, required) - $\sigma$ $[\mathrm{length}]$.

• n (float, required) - $n$ $[\mathrm{dimensionless}]$.

• m (float, required) - $m$ $[\mathrm{dimensionless}]$.

• delta (float, required) - $\Delta$ $[\mathrm{length}]$.

Type: TypeParameter [ tuple [particle_type, particle_type], dict]