PAS, parental aleination syndrome, legal recourse?

I believe my daughter has suffered from this since 17 years of age, she is now 34 and estranged from me.This is probably a moderate to severe case. Can I go after my xwife for defamation of character? I've recently been cut off from seeing my 2 grandchildren with this daughter, now no contact for 2 years. I had a good relationship with her before our separation in 1991. I wasn't aware of PAS until reading an article recently in the local newspaper this month! Now reflecting on the past with this new awareness I see many elements of PAS and believe myself and daughter are victims of this awful syndrome! My other 2 children son and daughter are fine, the middle child is the problem, 11 years old when her mother and I separated.