  We have investigated thermodynamic and dynamic properties as well as the
dielectric constant of water-metha\-nol model mixtures in the entire range of
composition by using constant pressure molecular dynamics simulations at
ambient conditions. The SPC/E and TIP4P/Ew water models are used in combination
with the OPLS united atom modelling for methanol. Changes of the average number
of hydrogen bonds between particles of different species and of the fractions
of differently bonded molecules are put in correspondence with the behavior of
excess mixing volume and enthalpy, of self-diffusion coefficients and
rotational relaxation times. From the detailed analyses of the results obtained
in this work, we conclude that an improvement of the description of an ample
set of properties of water-methanol mixtures can possibly be reached, if a more
sophisticated, carefully parameterized, e.g., all atom, model for methanol is
used. Moreover, exploration of parametrization of the methanol force field,
with simultaneous application of different combination rules for methanol-water
cross interactions, is required.
