Relation between Ultrasonically Measured Properties and the Coefficients in the Solid Equation of State

A relation is found by straight forward thermodynamic methods between the derivatives with respect to pressure of the isothermal and adiabatic bulk moduli which gives ${\mathrm{(\partial B}}_T{\mathrm{/\partial p)}}_T$ at zero pressure from the experimental ${\mathrm{(\partial B}}_s{\mathrm{/\partial p)}}_T$ plus temperature‐dependent‐only thermodynamic properties. Although B_T<B_s is required by thermodynamics, we find ${\mathrm{(\partial B}}_T{\mathrm{/\partial p)}}_T{\mathrm{>(\partial B}}_s{\mathrm{/\partial p)}}_T$ for Cu, Ag, Au, Al, NaCl, and Na. The coefficients a₁ and a₂ in the equation of state are evaluated from ultrasonic experimental data and compared with those obtained by experiments in high pressure physics. Agreement between the a₁'s is good but between the a₂'s it is poor.