[MMTK] nMoldyn and ft_window

Ramon Crehuet rcrehuet at gmail.com
Tue Dec 2 09:09:57 UTC 2008

Dear nMolDyn users,
I am using nMoldyn to calculate neutron scattering properties from a MD
simulation and I have a comment on the convolution of the incoherent
intermediate scattering function. I have read in the manual that the
ft_window option means the percentage of the width of the
time-resolution gaussian function over the total trajectory length.
Looking through the code, however, I have noticed that the time scale of
interest used to evaluate this percentage corresponds to the standard
deviation of the time-gaussian function (and not the width of the
gaussian function). Therefore, I deduce that when it comes to convert
the energy resolution gaussian function of an experiment, what must be
done is to calculate the standard deviation of this energy gaussian
function (from the "full width at half maximum" value) and converting it
to the corresponding time scale (inverse of the angular frequency 1/w).
In my opinion, the manual should give further details regarding this
confusing point taking into account the importance of the convolution in
the correct time scale in order to compare with experimental results.

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