Theoretical Study on chemical reactivity of Giemsa Stain by using DFT method

Abstract Structural properties for the Giemsa stain have been calculated using the density functional theory (B3LYP/(6-31G) included in the Gaussian 09 software which depends on quantum mechanics applications to conduct the theoretical calculation necessary for this study. Chemical activity and influence of Giemsa stain have been calculated through the calculation of the total energy, Gibbs free energy, entropy, standard heat of formation, dipole moment, Millikan’s atomic charge, bonds lengths, angles and bents, highest occupied molecular orbital and lowest unoccupied molecular orbital in order to identify the initiation of cracking in the molecule of the stain. This study indicates that Millikan’s atomic charge is divided into two main areas: the positive charge of the electron density is centralized on the hydrogen atoms, while the negative charge of the electron density is centralized on nitrogen and sulfur. The atomic charge of Giemsa stain is distributed on different atoms, since the nitrogen atoms carry negative charge (N21، N30) equal to -0,474 and 0,706 coulomb, subsequently. It has also been clear from the calculation occupied molecular orbital energy which equals to (-0.27217 eV) and the lowest unoccupied molecular orbital energy which equals to (-0.22435 eV), since the bandgap equals to 0.04782 eV. This study shows that bonds in C2-H14 and N30-H32 are most probably to interact (weakest bonds) out of the other twenty three bonds in Giemsa stain with a high probability of entering the division prophase in dissociation.