Fallout – How to get past the barriers before the vault

I played through Dead Money a few years ago, but I don't specifically remember the challenge you're facing.

It sounds like you're doing the quest Heist of the Centuries.

Nukapedia includes this section related to barriers before the vault:

After dispatching the three hologram emitters, you can turn off the security system at the last terminal. There is a terminal in a shelter on the lower catwalk on the other side of the room. This allows you to turn off all alarms.

After the room is quiet, drop down to the lower catwalk in the poison gas and grab the Vault turret terminal password tape. Activate the vault security turret terminal password as this shuts down the last set of force fields and speakers.

After entering the hall past the force fields, there is the Vault Security terminal which can be used to shut down the remaining security. (Note: Initially there are only two options: "Vault Security Protocols Information" and "Vault Security Protocols Warning," but after reading the first entry another option to disable security comes up.)

So it sounds like you need to "activate the vault security turret terminal password". That's not super clear as I'm not sure how you activate a password, but it sounds like there is a terminal you need to interact with, which is probably locked with a password you get immediately prior.

If you've done this and the barriers are still up, then you've likely encountered a bug. You should load a prior save and try again.