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probability command


probability style value 
  • style = max or diff
      max value = Pmax = fraction between 0.0 and 1.0
      diff value = M = multiplier on sum of diffusive distances 


    probability max 0.5
    probability diff 1.5 


    Set parameters that determine how binary reactions are computed for spatial simulations. A binary reaction occurs in a timestep with a probability P when a pair of reactant particles are within a cutoff distance R.

    The max style uses the specifed Pmax to set one distance R for all reactions so that the fastest reaction (maximum rate constant) will occur with probability Pmax and give the desired k for a well-mixed system with diffusion-limited reactions. Since other reactions happen less frequently (smaller rate constants) their P values are set smaller than the specified Pmax.

    The diff style sets a distance R for each reaction based on the diffusion coefficients of its 2 reactants. The sum of the root-mean squared value for each reactant is multipled by the specified M factor to compute R. The P for each reaction is then set so that each reaction happens at the desired frequency for a well-mixed system with diffusion-limitd reactions.

    Note that values of P and R for individual reactions can be overridden via the react_modify command.


    This command can only be used for spatial simulations.

    Related commands: none


    max 0.5