  In the present work we investigate a gas-liquid transition in a two-component
Gaussian core model, where particles of the same species repel and those of
different species attract. Unlike a similar transition in a one-component
system with particles having attractive interactions at long separations, and
repulsive interactions at short separations, a transition in the two-component
system is not driven solely by interactions, but by a specific feature of the
interactions, the correlations. This leads to extremely low critical
temperature, as correlations are dominant in the strong-coupling limit. By
carrying out various approximations based on standard liquid-state methods, we
show that a gas-liquid transition of the two-component system posses a
challenging theoretical problem.
