Ab initio calculation of atomic axial tensors and vibrational rotational strengths using density functional theory

The first application of the density functional theory (DFT) to the calculation of atomic axial tensors (AATs) is reported. Analytical derivative methods and gauge-invariant atomic orbitals (GIAOs) are employed. DFT/GIAO AATs for trans-2,3 d(2)-oxirane calculated using a [8s6p3d/6s3p] basis set and the Becke 3-Lee-Yang-Parr hybrid density functional, in combination with a DFT harmonic force field and atomic polar tensors (APTs), yield vibrational rotational strengths in better agreement with experiment than comparable calculations at the Hartree-Fock level. The largest remaining deviations between theory and experiment are attributed to experimental error.