COMPUTATIONAL DENSITY-FUNCTIONAL THEORY VIBRATIONAL-SPECTRA OF CUBANE

The performance of various Density Functional Theory (DFT) functionals and additional frequency scaring for predicting cubane vibrational ha rmonic frequencies is evaluated. All studied DFT functionals give more accurate frequencies (i.e., in better agreement with experimental val ues) not only than Hartree-Fock calculations (as expected) but also be tter than performed localized MP2 (LMP2) calculations. This accuracy c an be additionally enhanced by frequency scaling, The B3LYP, B3PW91 an d SVWN functionals are best suited for evaluation of vibrational frequ encies of cubane. However, SVWN functional performs more poorly than o ther DFT functionals in reproducing cubane geometry.