Perturbation calculation of thermodynamic density of states.
The density of states g (ε) is frequently used to calculate the temperature-dependent properties of a thermodynamic system. Here a derivation is given for calculating the warped density of states g*(ε) resulting from the addition of a perturbation. The method is validated for a classical Heisenberg model of bcc Fe and the errors in the free energy are shown to be second order in the perturbation. Taking the perturbation to be the difference between a first-principles quantum-mechanical energy and a corresponding classical energy, this method can significantly reduce the computational effort required to calculate g(ε) for quantum systems using the Wang-Landau approach.
Computational Science and Mathematics Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA.
G
G
Brown
T C
TC
Schulthess
D M
DM
Nicholson
M
M
Eisenbach
G M
GM
Stocks
D008962:Models, Theoretical; D013696:Temperature; D013816:Thermodynamics