# bond_style oxrna2/fene command¶

## Syntax¶

bond_style oxdna/fene

bond_style oxdna2/fene

bond_style oxrna2/fene


## Examples¶

bond_style oxdna/fene
bond_coeff * 2.0 0.25 0.7525

bond_style oxdna2/fene
bond_coeff * 2.0 0.25 0.7564

bond_style oxrna2/fene
bond_coeff * 2.0 0.25 0.76107


## Description¶

The oxdna/fene , oxdna2/fene and oxrna2/fene bond styles use the potential

$E = - \frac{\epsilon}{2} \ln \left[ 1 - \left(\frac{r-r_0}{\Delta}\right)^2\right]$

to define a modified finite extensible nonlinear elastic (FENE) potential (Ouldridge) to model the connectivity of the phosphate backbone in the oxDNA/oxRNA force field for coarse-grained modelling of DNA/RNA.

The following coefficients must be defined for the bond type via the bond_coeff command as given in the above example, or in the data file or restart files read by the read_data or read_restart commands:

• $$\epsilon$$ (energy)

• $$\Delta$$ (distance)

• $$r_0$$ (distance)

Note

The oxDNA bond style has to be used together with the corresponding oxDNA pair styles for excluded volume interaction oxdna/excv , stacking oxdna/stk , cross-stacking oxdna/xstk and coaxial stacking interaction oxdna/coaxstk as well as hydrogen-bonding interaction oxdna/hbond (see also documentation of pair_style oxdna/excv). For the oxDNA2 (Snodin) bond style the analogous pair styles oxdna2/excv , oxdna2/stk , oxdna2/xstk , oxdna2/coaxstk , oxdna2/hbond and an additional Debye-Hueckel pair style oxdna2/dh have to be defined. The same applies to the oxRNA2 (Sulc1) styles. The coefficients in the above example have to be kept fixed and cannot be changed without reparameterizing the entire model.

Example input and data files for DNA and RNA duplexes can be found in examples/USER/cgdna/examples/oxDNA/ , /oxDNA2/ and /oxRNA2/. A simple python setup tool which creates single straight or helical DNA strands, DNA/RNA duplexes or arrays of DNA/RNA duplexes can be found in examples/USER/cgdna/util/.

Please cite (Henrich) in any publication that uses this implementation. The article contains general information on the model, its implementation and performance as well as the structure of the data and input file. The preprint version of the article can be found here. Please cite also the relevant oxDNA/oxRNA publications. These are (Ouldridge) and (Ouldridge-DPhil) for oxDNA, (Snodin) for oxDNA2, (Sulc1) for oxRNA2 and for sequence-specific hydrogen-bonding and stacking interactions (Sulc2).

## Restrictions¶

This bond style can only be used if LAMMPS was built with the USER-CGDNA package and the MOLECULE and ASPHERE package. See the Build package doc page for more info.

## Default¶

none

(Henrich) O. Henrich, Y. A. Gutierrez-Fosado, T. Curk, T. E. Ouldridge, Eur. Phys. J. E 41, 57 (2018).

(Ouldridge-DPhil) T.E. Ouldridge, Coarse-grained modelling of DNA and DNA self-assembly, DPhil. University of Oxford (2011).

(Ouldridge) T.E. Ouldridge, A.A. Louis, J.P.K. Doye, J. Chem. Phys. 134, 085101 (2011).

(Snodin) B.E. Snodin, F. Randisi, M. Mosayebi, et al., J. Chem. Phys. 142, 234901 (2015).

(Sulc1) P. Sulc, F. Romano, T. E. Ouldridge, et al., J. Chem. Phys. 140, 235102 (2014).

(Sulc2) P. Sulc, F. Romano, T.E. Ouldridge, L. Rovigatti, J.P.K. Doye, A.A. Louis, J. Chem. Phys. 137, 135101 (2012).