[ESPResSo-users] Virtual sites relative & Interactions.

[Rohit Goswami]

On creating a molecular cluster using the relative virtual sites implementation,
I'm unable to see any interactions between the virtual particles.
ie.
inter 1 5 lennard-jones $::ljja_eps $::ljja_sig $::ljja_rcut $::ljja_roff 
$::ljja_rcap $::ljja_rmin 
where 1 is a virtual particle type and 5 is a regular particle.
The above command has no effect on the simulation whatsoever.
using 
puts "[analyze energy nonbonded 1 5]"
gives only 0.0

Is this meant to happen? As such how does one define interactions with virtual 
sites then?