  The simplest anharmonic characteristics of Ir and Rh are discussed in the
framework of a previously developed simple pseudopotential model which
describes the elastic moduli, phonon spectra and the lattice heat capacity in
the harmonic approximation of these metals succesfully. The microscopic
Gruneisen parameters, the dependences of the elastic moduli on pressure, the
coefficient of thermal expansion and the equations of state at the finite
temperatures have been calculated. The ab initio calculations of the
energy-band structure and the equation of state for Ir at T=0 have been done to
test the model for adequacy at high pressures. The values of different
contributions (zero-point oscillations, quasiharmonic, etc.) in the considered
thermodynamic characteristics of Ir and Rh are discussed.
