VIBRATIONAL-SPECTRA AND AB-INITIO STUDY ON VIBRATIONAL FREQUENCIES AND CONFORMATION FOR 4-METHYL-3-PENTEN-2-ONE

IR and Raman spectra were measured for 4-methyl-3-penten-2-one. The sp ectra were interpreted with the aid of normal coordinate calculations by ab initio method at HF/3-21G and HF/6-31G levels. Molecular confor mation calculations were made for four possible conformers of the comp ound using 3-21G and 6-31G basis sets. Calculated results show that: (1) 4-methyl-3-penten-2-one exists mainly in one stable conformer (s-c is); (2) calculated vibrational frequencies of s-cis conformer are in good agreement with the experimental values. (C) 1998 Elsevier Science B.V.