The structural, energetic, electronic, and mechanical properties of a series of metal−organic framework (MOF) materials have been systematically studied with the density functional based tight-binding method. The cubic array of Zn4O(CO2)6 units (connectors) connected by different types of organic secondary building blocks (linkers) was considered. The results show that these materials are stable with bulk moduli ranging from 0.5 to 24 GPa with decreasing size of the linker. All MOFs are semiconductors or insulators with band gaps between 1.0 and 5.5 eV, mainly determined by highest occupied molecular orbital−lowest unoccupied molecular orbital gaps of the linker molecules. The atomic charges are nearly the same for free building blocks and the solid MOFs.
J. Phys. Chem. B, 2007, V. 111, № 28, P. 8179 - 8186.

For molecular substances exhibiting harmonic and nonharmonic vibrations, we present a first-principles approach to predict enthalpy differences between phases at finite temperatures, including solid-solid and melting. We apply it to the complex hydride LiBH4. Using ab initio molecular dynamics, we predict a structure for the high-T solid phase of lithium borohydride, and we propose an approximation to account for nonharmonic vibrations. We then predict the enthalpy changes for solid-solid transition, melting, and an H-storage reaction, all in agreement with experiment.
PRL 100, 040602 (2008). DOI: 10.1103/PhysRevLett.100.040602 PACS numbers: 05.70.-a, 63.10.+a, 64.70.-p, 82.20.Wt