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hoomd_script.pair Namespace Reference

Commands that create forces between pairs of particles. More...

Classes

class  coeff
 Defines pair coefficients. More...
 
class  nlist
 Interface for controlling neighbor list parameters. More...
 
class  pair
 Generic pair force. More...
 
class  lj
 Lennard-Jones pair force. More...
 
class  gauss
 Gaussian pair force. More...
 
class  slj
 Shifted Lennard-Jones pair force. More...
 
class  yukawa
 Yukawa pair force. More...
 
class  ewald
 Ewald pair force. More...
 
class  cgcmm
 CMM coarse-grain model pair force. More...
 
class  table
 Tabulated pair force. More...
 
class  morse
 Morse pair force. More...
 
class  dpd
 NVT Integration via Dissipative Particle Dynamics pair force. More...
 
class  dpd_conservative
 DPD Conservative pair force. More...
 
class  eam
 EAM pair force. More...
 
class  dpdlj
 NVT Integration via Dissipative Particle Dynamics pair force with a Lennard Jones conservative force. More...
 
class  force_shifted_lj
 Force-shifted Lennard-Jones pair force. More...
 
class  moliere
 Moliere pair force. More...
 
class  zbl
 ZBL pair force. More...
 
class  tersoff
 Tersoff Potential. More...
 

Detailed Description

Commands that create forces between pairs of particles.

Generally, pair forces are short range and are summed over all non-bonded particles within a certain cutoff radius of each particle. Any number of pair forces can be defined in a single simulation. The net force on each particle due to all types of pair forces is summed.

Pair forces require that parameters be set for each unique type pair. Coefficients are set through the aid of the coeff class. To set this coefficients, specify a pair force and save it in a variable

1 my_force = pair.some_pair_force(arguments...)

Then the coefficients can be set using the saved variable.

1 my_force.pair_coeff.set('A', 'A', epsilon=1.0, sigma=1.0)
2 my_force.pair_coeff.set('A', 'B', epsilon=1.0, sigma=2.0)
3 my_force.pair_coeff.set('B', 'B', epsilon=2.0, sigma=1.0)

This example set the parameters epsilon and sigma (which are used in pair.lj). Different pair forces require that different coefficients are set. Check the documentation of each to see the definition of the coefficients.

See Also
Quick Start Tutorial