			15min:

AB INITIO AND DFT CALCULATIONS FOR THE VIBRATIONAL FREQUENCIES AND BARRIER TO PLANARITY OF CYCLOPENTENE AND ITS DEUTERATED ISOTOPOMERS.

ABDULAZIZ AL-SAADI AND JAAN LAANE, Department of Chemistry, Texas A&M University, College Station, TX 77843-3255.

Ab initio and DFT calculations have been carried out for the cyclopentene molecule in order to analyze its structure and vibrational frequencies. The structure was calculated with MP2/6-311++G** and MP2/cc-pVTZ basis sets and these predicted puckering angles of 27.1^\circ and 26.1^\circ, respectively, as compared to the experimental far-infrared value of 26^\circ. The barrier to planarity was calculated to be 247 cm^-1, slightly higher than the 233 cm^-1 far-infrared value. The calculated vibrational frequencies from DFT-B3LYP/cc-pVTZ were compared to the experimental values for the d₀, d₁, d₄, and d₈ isotopomers and several vibrational reassignments were made.