Bond fluctuation model: Difference between revisions
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This model exhibits some advantages with respect to more conventional representations of the polymer in a lattice, such as the fixed-bond [[self-avoiding walk chain model]] on a simple cubic lattice: | Polymers have many interesting mesoscopic properties that can adequately represented through coarse-grained models. Lattice models are particularly useful since they employ integer coordinates that can be quickly processed. Another advantage is the possibility of checking the occupancy of the discrete number of sites and store it in an array. Therefore, overlapping between beads can be easily avoided. | ||
The '''bond fluctuation model''' has been used in the recent past to simulate a great variety of [[Polymers |polymer]] systems (see Ref.s 1 and 2). It represents 8-site non-overlapping beads placed in a [[Building up a simple cubic lattice | simple cubic lattice]]. Bonds linking the beads may have lengths ranging between 2 and <math>\sqrt 10</math>, but bonds vectors of the type (2,2,0) are excluded to avoid bond crossing during the simulation. | |||
This model exhibits some advantages with respect to more conventional representations of the polymer in a lattice, such as the fixed-bond [[self-avoiding walk chain model]] on a simple cubic or tetrahedrical lattice: | |||
*It is somehow more consistent with the theoretical description of the chain through Gaussianly distributed statistical segments. This description has been employed in the past to obtain useful analytical expression for equilibrium properties and its dynamical version corresponds to the [[Rouse model]]. | *It is somehow more consistent with the theoretical description of the chain through Gaussianly distributed statistical segments. This description has been employed in the past to obtain useful analytical expression for equilibrium properties and its dynamical version corresponds to the [[Rouse model]]. | ||
*A variety of bond lengths alleviate the restrictions due to the lattice constraints and, therefore, the model is more similar to the continuum behavior. | *A variety of bond lengths alleviate the restrictions due to the lattice constraints and, therefore, the model is more similar to the continuum behavior. | ||
Revision as of 15:35, 30 May 2007
Polymers have many interesting mesoscopic properties that can adequately represented through coarse-grained models. Lattice models are particularly useful since they employ integer coordinates that can be quickly processed. Another advantage is the possibility of checking the occupancy of the discrete number of sites and store it in an array. Therefore, overlapping between beads can be easily avoided.
The bond fluctuation model has been used in the recent past to simulate a great variety of polymer systems (see Ref.s 1 and 2). It represents 8-site non-overlapping beads placed in a simple cubic lattice. Bonds linking the beads may have lengths ranging between 2 and , but bonds vectors of the type (2,2,0) are excluded to avoid bond crossing during the simulation.
This model exhibits some advantages with respect to more conventional representations of the polymer in a lattice, such as the fixed-bond self-avoiding walk chain model on a simple cubic or tetrahedrical lattice:
- It is somehow more consistent with the theoretical description of the chain through Gaussianly distributed statistical segments. This description has been employed in the past to obtain useful analytical expression for equilibrium properties and its dynamical version corresponds to the Rouse model.
- A variety of bond lengths alleviate the restrictions due to the lattice constraints and, therefore, the model is more similar to the continuum behavior.
- It is possible to perform simulations by using a single type of elementary bead jump. This is a difference with respect to the simple cubic lattice model where a combination of bent and crankshaft elementary moves has to be used as the simplest local level. The implication is that one can generate dynamic trajectories with the bond fluctuation model by using a simple and natural type of bead jumps, which intuitively resembles the stochastic behavior of Brownian particles.
- The elementary jump moves can directly used in polymers with branch points (stars, combs, dendrimers).