Bobby Brown's Wife -- Praying for Bobbi Kristina ... Beef with Nick Gordon

Bobby Brown's wife left Bobbi Kristina and her husband in Atlanta and flew to L.A., where she made 2 things clear ... they still have hope, and they want nothing to do with Nick Gordon.

Alicia Etheredge landed in L.A. Wednesday and told our photog their hope for Bobbi Kristina's survival is prayer. We asked about the doctors advising Bobby to make a decision on withdrawing life support, but her focus is God.

Alicia -- who is pregnant -- bristled when Nick Gordon's name came up. As we reported, Nick is now going public, trying to put pressure on the Brown family, to let him see Bobbi Kristina, but Alicia's reaction makes it clear ... he's persona non grata.