CALCULATED VIBRATION FREQUENCIES AND IR ABSORPTION INTENSITIES OF [6] CYCLACENE (CHIRAL) MOLECULE

Abstract

ABSTRACT.:Density Functional Theory (DFT) of the type (B3LYP) and a Gaussian basis (6-311G)was applied for calculating the vibration frequencies and IR absorption intensities for normalcoordinates of the ([6] Cyclacene (Chiral), with (D3d) symmetry) molecule. Comparison of the resultsshowed that for the C-H stretching vibrations the sym. modes show higher frequency values than theasym. And the inverse for C-C stretching vibrations.As for the CH and CC deformation the asym. vibrations where of lower frequency values than thesym.;sym.CH str. > asym. CH str.sym CC str. < asym. CC str. C=C str. (circum.) >  C--C str. (axial.) >  C-C str. (circum.)And,sym. δCH > asym. δCHsym. CH < asym. CHδCH (rocking) > δCH (scissoring)CH (twisting) > CH (wagging)Where axial are the vertical C-C bonds (annular bonds) in the rings and circumferential are the outerring bonds.The results include the assignment of all puckering, breathing and clock-anticlockwise bendingvibrations. Also calculations and studying the distribution of electronic density on the atoms of themolecule. They allow a comparative view of the charge density at the carbon atoms too