OF cis-trans AND trans-trans FORMIC ACID DIMERS.Potential energy surface (PES) of cis-trans and trans-trans formic acid dimers were sampled using a stochastic method, and the geometries, energies, and vibrational frequencies were computed at B3LYP/6-311++G(3df,2p) level of theory.The results show that molar free energy of dimerization deviated up to 108.4% when basis set superposition error (BSSE) and zero-point energy (ZPE) were not considered.For cis-trans dimers, C=O and O-H bond weakened, whereas C-O bonds strengthened due to dimerization.Also, transtrans FA dimers did not show a trend regarding strengthening or weakening of the C=O, O-H and C-O bonds.
