  In this article we investigate and develop specific aspects of
Friedmann-Robertson-Walker (FRW) scalar field cosmologies related to the
interpretation that canonical and phantom scalar field sources may be
interpreted as cosmological configurations with a mixture of two interacting
barotropic perfect fluids: a matter component $\rho_1(t)$ with a stiff equation
of state ($p_1=\rho_1$), and an "effective vacuum energy" $\rho_2(t)$ with a
cosmological constant equation of state ($p_2=-\rho_2$). An important
characteristic of this alternative equivalent formulation in the framework of
interacting cosmologies is that it gives, by choosing a suitable form of the
interacting term $Q$, an approach for obtaining exact and numerical solutions.
The choice of $Q$ merely determines a specific scalar field with its potential,
thus allowing to generate closed, open and flat FRW scalar field cosmologies.
