Theoretical Calculation of Vibrational Circular Dichroism Spectra

摘要

We report calculations of the mid-IR unpolarized absorption and circulardichroism spectra of 4-methyl-2-oxetanone, 6,8-dioxabicyclo3.2.1octane and 1,7,7-trimethylbicyc lo2.2.1heptan-2-one (camphor) based on harmonic force fields calculated using Density Functional Theory (DFT). A hybrid density functional--Becke3LYP--is used. The basis set is 6-31G. The results are in impressive agreement with experimental spectral calculations using the LSDA and BLYP functionals are much less successful. Our results using Becke3LYP/DFT are compared to the predictions of SCF and MP2 calculations. At the present time, the Becke3LYP/DFT methodology is clearly to be preferred in predicting mid-IR vibrational spectra.