The extended Perdew-Burke-Ernzerhof functional with improved accuracy for thermodynamic and electronic properties of molecular systems

A study on the Perdew-Burke-Ernzerhof (PBE) functional for predicting the unacceptable errors in the thermomechanical data of molecular systems was discussed. Density functional theory (DFT) methods that included Hartee-Fork exchange (HF) and post-HF methods were applied for the study of molecular structures. Four free parameters were chosen PBE theory against experimental data and the van der Waals interaction properties of Ne ₂ which lead to xPBE extended functional. It was observed that xPBE enlarged the field of applications available for pure DFT.