Theoretical thermodynamic study of Pyrazole in the gas phase at the different temperatures

The thermodynamic functions such as enthalpy (H), Gibbs free energy (G) and entropy (S) of Pyrazole was theoretically studied at 5 different temperatures 25, 30, 35, 40 and 45°C by using Gussian o3, software. First, the structural optimization of isolated Pyrazole was done in the gas phase by appling the Density Functional Theory (B3LYP) level with 3-21G, 6-31G and 6-31+G(d) basis sets. Moreover, vibrational frequencies were calculated in gas phase on the optimized geometries at the same level of theory to obtain enthalpy, Gibbs free energy and entropy at 5 different temperatures.Finally the temperature effects on the thermodynamic functions were discussed.