# OEGasteigerInitialCharges¶

bool OEGasteigerInitialCharges(OEMolBase &mol)

Calculates the seed charge partial charges used by the Marsilli-Gasteiger partial charge algorithm.

Gasteiger initial charges assign the partial charge of -0.5 to atoms of type OETriposType::Oco2, i.e. carboxylate oxygens, and use the formal charge as the partial charge on all other atoms except those in conjugated rings. For conjugated ring systems, consisting of Tripos atom types OETriposType::C2, OETriposType::Car, OETriposType::N2, OETriposType::Nar, OETriposType::Npl3 and OETriposType::Nam, the sum of the formal charges of the atoms in the ring system are divided equally amongst all atoms in the ring system. For example, the five heavy atoms in imidazolium ([nH+]1c[nH]cc1), each get a partial charge of 0.2. O

Warning

It is not necessary to call OEGasteigerInitialCharges function prior to calling OEGasteigerPartialCharges function.