ABINIT Discussion Forums

Dear All
i'm trying to find the Total energy of a molecule at High temperature.
How can we set the temperature of a molecule in ABINIT?

Well, a single molecule doesn't have a temperature in the thermodynamic sense of the word, because temperature implies the thermal equilibrium (conjugate to entropy) of a many-particle system. If you wanted to mimic this in abinit you would need to embed your test molecule in a bath of other, inert particles (argon atoms or something like that) and do an ab initio MD calculation. The argon is needed to serve as an energy bath. If you want to stick with one molecule only, then you need to work out by single point energy calculations the anharmonicities of all the vibrational degrees of freedom, and also the change in moments of inertia with distortion, and then populate them all according to a Boltzmann distribution at the temperature you are interested in. That would give some information about what the thermodynamics of this molecule is like as a function of temperature.

Thank Sir,
Actually i need it for a bulk system only. i misspelled it.