Dragoni, DanieleCeresoli, DavideMarzari, Nicola2015-04-132015-04-132015-04-13201510.1103/PhysRevB.91.104105https://infoscience.epfl.ch/handle/20.500.14299/113180WOS:000350845400002We calculate the thermomechanical properties of alpha-iron, and in particular its isothermal and adiabatic elastic constants, using first-principles total-energy and lattice-dynamics calculations, minimizing the quasiharmonic vibrational free energy under finite strain deformations. Particular care is made in the fitting procedure for the static and temperature-dependent contributions to the free energy, in discussing error propagation for the two contributions separately, and in the verification and validation of pseudopotential and all-electron calculations. We find that the zero-temperature mechanical properties are sensitive to the details of the calculation strategy employed, and common semilocal exchange-correlation functionals provide only fair to good agreement with experimental elastic constants, while their temperature dependence is in excellent agreement with experiments in a wide range of temperature almost up to the Curie transition.text::journal::journal article::research article