“…This, and the fact that the non-autonomous h belongs to the space L 2 loc (R; H −1 (Ω)), are the main novelties of our problem. The lack of compactness of the injection H 1 0 (Ω) ⊂ L 2 (Ω) (in the case of unbounded domains) implies that the standard techniques previously used, particularly the one involving the so-called flatenning property (see [Kloeden & Langa, 2007], [Li & Zhong, 2007], [Song & Wu, 2007], [Wang & Zhong, 2008], amongst others), which have been successfully used when Ω is bounded and h ∈ L 2 loc (R; L 2 (Ω)), do not work in our case.…”