Grand-canonical quantized liquid density-functional theory in a Car-Parrinello implementation

Quantized Liquid Density-Functional Theory (QLDFT) [S. Patchkovskii and T. Heine, Phys. Rev. E 80, 031603 (2009)], a method developed to assess the adsorption of gas molecules in porous nanomaterials, is reformulated within the grand canonical ensemble. With the grand potential it is possible to compare directly external and internal thermodynamic quantities. In our new implementation, the grand potential is minimized utilizing the Car-Parrinello approach and gives, in particular for low temperature simulations, a significant computational advantage over the original canonical approaches. The method is validated against original QLDFT, and applied to model potentials and graphite slit pores. (C) 2013 AIP Publishing LLC.