  This paper presents the modeling of the F9 V star beta Virginis based on
seismological measurements. Using the Geneva evolution code including rotation
and atomic diffusion, we find that two distinct solutions reproduce all
existing asteroseismic and non-asteroseismic observational constraints well: a
main-sequence model with a mass of 1.28 +- 0.03 Msun and an age t = 3.24 +-
0.20 Gyr, or a model in the post-main sequence phase of evolution with a lower
mass of 1.21 +- 0.02 Msun and an age t = 4.01 +- 0.30 Gyr. The small spacings
and the ratio between small and large spacings are sensitive to the differences
in the structure of the central layers between these two solutions and are also
sensitive to the structural changes due to the rotational mixing. They can
therefore be used to unambiguously determine the evolutionary state of beta Vir
and to study the effects of rotation on the inner structure of the star.
Unfortunately, existing asteroseismic data do not enable such precise
determination. We also show that the scatter in frequencies introduced by the
rotational splittings can account for the larger dispersion of the observed
large spacings for the non-radial modes than for the radial modes.
