Semiclassical fifth virial coefficients for improved ab initio helium -‐ 4 standards
نویسندگان
چکیده
For helium-4, we present ab initio, semiclassical calculations of virial coefficients B n for n = 2, 3, 4, and 5 from 50 K to 1000 K. Using our values of B 4 and B 5 and the more accurate literature values of B 2 and B 3 , we argue that the ab initio virial equation of state is more accurate than recent, high-quality, densimeter measurements spanning the range {223 K < T < 500 K, p < 38 MPa}. Thus, the present values of B 4 and B 5 extend the useful temperature and density range of ab initio helium standards.
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