Theoretical Methodology
The optimized geometries of the neutral and charged states of the molecules were generated at the DFT level using B3LYP hybrid functional and 6-31 G**(d,p) basis set which are considered to provide enough accuracy as performed in the Gaussian 09 package [53]. The electronic excitation energies and the absorption spectra for two pyrazole derivatives in the absence of solvent are computed with the time-dependent density functional theory (TD-DFT) at the B3LYP/6-31G** (d,p) level. In addition, the molecular ionization potential (IP) and electron affinity (EA), inner reorganization energy were calculated [54].