513.001 Molecular and Solid State Physics | |
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Compressibility of NaClThe cohesive energy of a NaCl crystal can be described by the equation The material parameters for NaCl are ρ = 0.321 Å, zλ = 1.05×10-8 erg, and α = 1.748. Here R is the distance between nearest neighbors. Calculate the bulk modulus B = -V(dp/dV) and the compressibility κ = 1/B of an ideal sodium chloride crystal at T = 0 K. Here V is the volume and p is the pressure. The lattice constant of NaCl is 0.564 nm. At T = 0 K, the entropy is zero so the total cohesive energy is Utot = -p dV. This means that the bulk modulus at low temperature is, . 1 erg = 10-7 J. |