Experimental Verification of Van der Waals parameters?

I am currently trying to find an academic paper that experimentally verifies the a and b values of Van der Waals forces for carbon dioxide. I can't seem to find this, and am wondering if I am missing something. Could somebody either give me a reason this is so hard to find, or link me a paper I have proven myself incapable of finding?


If this is impossible, is there a paper that empirically computes the answer?


