Studies of structure, vibrational frequencies and thermodynamics of UO6

After molecular structure of UF6 is optimized, molecular vibrational frequencies are calculated by LDA and GGA approaches. Some thermodynamic parameters are calculated based on the principle of statistic mechanics. Various functionals such as PWC, VWN, VWNPB, PW91, BP, PBE, RPBE, BOP with various basis sets such as MIN, DN, DND and DNP are used. The small basis sets, MIN and DN, can arrive at self-consistency. DMol3 can save more CPU's time and resource than all electron calculations including Hartree-Fock and DFT with Gaussian code, so it should be introduced in some research, especially on compounds of lanthanide and actinide. However, comparing with the results from classical DFT, the new calculation may accompany a rather larger error. (authors)