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 .