The energy surface of the urea molecule was studied at the Mller-Plesset, B-LYP and B3-LYP density functional levels. The scanning of the energy surface indicates the presence of two energy minima corresponding to nonplanar C2 and Cs symmetry structures. The C2 symmetry structure is the most stable one, while the Cs symmetry isomer lies 6 kJ mol -1 above the lowest energy minimum. The infrared spectra of the C2 symmetry stable isomer were computed at the MP2/DZ(d,p), B-LYP/DZ(d,p), B-LYP/6-311+G(d,p) and B3-LYP/6-311++G(2d,p) levels and the assignment of the harmonic vibrational frequencies was accomplished through the calculated potential energy distribution of urea and urea-d4. The comparison between the MP2/DZ(d,p) and B-LYP/DZ(d,p) infrared spectra of the C2 and Cs symmetry isomers is presented and discussed. 1997 by
No takes yet. Share an insight, caveat, or question.
Spoliti et al. (1997) studied this question.