Hello desperado13,
Welcome to the Parenting board!
You are facing a really tough situation with your daughter, I am so sorry, this must be frightening and so so sad... .
We are here to listen and to support you the best we can as peers.
First things first: your daughter's immediate safety is the priority. Has your daughter attempted suicide before? Has she ever talked about how she would do it? It might give you clues and an opportunity to possibly remove the means (whether it's pills, sharp objects etc.)
If you believe she is acutely suicidal, the best thing is probably to take her to the ER. There is a really good workshop here on the site about how to deal with this issue:
Dealing with threats of Suicide and Suicide Attempts if you have a chance, please read it - I think you will find it helpful.
You are right that if your daughter doesn't cooperate, any help she is given may not work in the end. However, it may be that the RTCs she has been in did not offer the right help she needs. Searching for the right RTC and interviewing them is a difficult process and sometimes it's a matter of luck. We do have a sub-section dedicated to threads about RTCs among others, I encourage you to read through it:
Archive: Hospitalization, RTCs, and IOPs. Please don't give up hope just yet, you may be able to find just what your daughter needs... .
We also have a brand new thread about an RTC today that sounds hopeful:
https://bpdfamily.com/message_board/index.php?topic=237017.0Keep posting, this is a safe and supportive place for weary parents.