  We present a self-consistent prediction of the interstellar radiation field
(ISRF), from the extreme ultraviolet (EUV) to sub-mm range, based on two
chemical evolution models of a Milky Way-like galaxy (MWG). To this end, we
develop a new tool called Mixclask to include gas emission, absorption and
scattering from the photoionization code Cloudy into the Monte Carlo radiative
transfer code Skirt. Both algorithms are invoked iteratively, until the
physical properties of the ISM converge. We have designed a first test,
reminiscent of a HII region, and we find that the results of Mixclask are in
good agreement with a spherically symmetric Cloudy simulation. Both MWG models
based on chemical evolution codes give results broadly consistent with previous
empirical models reported in the literature for the ISRF of our Galaxy, albeit
they systematically underestimate the mid-infrared emission. We also find
significant differences between our two models in the whole ultraviolet range,
not fully explored in previous ISRF models. These results show the feasibility
of our method of combining radiative transfer with chemical evolution models:
there is increased predictive power and the interstellar radiation field
obtained provides further constraints on the model parameters. Python source
code to implement our method is publicly available at
https://github.com/MarioRomeroC/Mixclask.
