Equations of state

Damian C. Swift, P-24

Equations of state (EOS) are thermodynamic functions important in describing the behavior of materials at high pressure and temperature. EOS are of interest weapons, geophysics, and astrophysics; they are needed for hydrocode simulations e.g. of shock wave and impact problems. Over a wide range of conditions, the EOS can be understood and predicted using quantum mechanics to describe the electron states and the motion of atoms. EOS can be inferred and tested experimentally with shock wave experiments and other high pressure techniques. Experimental difficulties mean that purely empirical EOS can be unreliable; an example is the controversy over sonoluminescence-induced thermonuclear fusion in deutero-acetone. Conversely, practical treatments of the electron many-body problem limit the accuracy of purely theoretical EOS.