Density functional and post Hartree-Fock equilibrium geometries, potential energy surface and vibrational frequencies for methylamine

The equilibrium structure, the potential energy surface and the infrared harmonic frequencies are determined by using two generalized gradient approximation density functional methods for methylamine. The results are compared to those of a second-order Mّller-Plesset and coupled cluster calculations. The DFT methods predict correctly the equilibrium geometry, the inversion energy barrier and the infrared spectra. The B-P86 method show better agreement with the experiment than the MP2 or CCD methods.