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

EXCLUSIVE

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.