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 ca lculation of atomic axial tensors (AATs) is reported. Analytical deriv ative 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 functiona l, in combination with a DFT harmonic force field and atomic polar ten sors (APTs), yield vibrational rotational strengths in better agreemen t with experiment than comparable calculations at the Hartree-Fock lev el. The largest remaining deviations between theory and experiment are attributed to experimental error.