SOME ASPECTS OF THERMAL AND ELASTIC PROPERTIES OF YTTRIUM

A systematic calculation of the lattice heat capacity, third-order elastic constants and the temperature variation of the effective Grueneisen functions of the hexagonal close-packed metal yttrium is carried out. The normalized frequency distribution function employed for specific heat calculations is obtained using 50880 frequencies. Good agreement is found between the calculated and experimental C//v**1 values. The 10 third-order elastic constants are evaluated using two anharmonic parameters and these, in turn, are utilized to calculate the low-temperature limit of thermal expansion, the Anderson-Grueneisen (A-G) parameter, and the second Grueneisen constant of yttrium. The temperature dependence of the volume Grueneisen function and its high-temperature limit are determined. The variation of the lattice parameters of yttrium with hydrostatic pressure is also investigated.