GROMACS version:2019.2

GROMACS modification: No

The Gromacs reference manual suggests that it is possible to calculate an angle dependent RDF using gmx rdf (Radial distribution functions — GROMACS 2021 documentation).

However I cannot find how to implement this using gmx rdf; there are no options to call for angle dependence listed in gmx rdf -h, for example. Can anyone suggest how I would to specify the angle of interest to gmx rdf?

Any help on this would be much appreciated!

Hi,

you can compute rdf around axes parallel to the *z* -axis using gmx rdf and option `-xy`

Best regards

Alessandra

Hi Alessandra

Thank you for the response. The problem I have is that I am trying to get the RDF at some arbitrary angle, it is not necessarily parallel to -z. The reference manual suggests it is possible, so I am probably missing something trivial, but I am a bit lost with how to do it.

Thank you

R

Hi,

Do you refer to the following sentence?

" With gmx rdf it is also possible to calculate an angle dependent rdf gAB(r,θ), where the angle θ is defined with respect to a certain laboratory axis e, (…) This gAB(r,θ) is useful for analyzing anisotropic systems. **Note** that in this case the normalization ⟨ρB⟩local,θ is the average density in all angle slices from θ to θ+dθ up to rmax, so angle dependent, see Fig. 52 D? "

Best regards

Alessandra

Hi Alessandra

Yes this is exactly what I read; this would be exactly the sort of analysis I would like to perform.

BW

R