Theoretical studies of molecular structure and vibrational spectra of melaminium citrate

The molecular geometry and vibrational frequencies of melaminium citrate in the ground state have been calculated using the Hartree-Fock (HF) and density functional method (B3LYP) with 6-31G(d) basis set. The optimized geometric bond lengths and bond angles obtained by using HF and density functional theory (DFT, B3LYP) show the best agreement with the experimental data. Comparison of the observed fundamental vibrational frequencies of melaminium citrate and calculated results by density functional B3LYP and Hartree-Fock methods indicate that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems.