Therotical studies of the vibrational spectra of methyl-N-(1-naphthyl)-urethane

Optimized geometries, vibrational force fields and infrared intensities of methyl - N - (1 naphthyl) - urethane were calculated by HF and DFT(B3LYP) m ethods with 6 - 31G* * basis set. The theoretical force fields were scaled using the scaled quantum mechanical method of Pulay. Then normal mode analy sis of the two vibrational force fields was carried out. The calculated inf rared spectra were compared with the experimental results of Zavodov in dil ute solutions. The average deviations between the experimental and computed frequencies were 37. 8 and 8. 68 cm(-1) for HF/6 - 31G* * and B3LYP/6 - 31 G* * methods, respectively. In addition, the whole vibrations modes were as signed according to the calculated potential energy distribution and the in frared intensities.