Gi. Cardenasjiron et A. Torolabbe, A MODEL POTENTIAL FOR THE INTERNAL-ROTATION OF NITROSYL HYPERFLUORITE- A COMPARATIVE-ANALYSIS OF DIFFERENT THEORETICAL METHODS, Chemical physics letters, 222(1-2), 1994, pp. 8-14
We present a comparative analysis of the internal rotation energy curv
es of nitrosyl hyperfluorite (FO-NO). Two model potentials, derived fr
om a Fourier series expansion, have been used to rationalize the trans
half arrow right over half arrow left cis isomerization process for d
ifferent theoretical methods going from traditional molecular orbital
calculations to density functional theory. It is shown that Hartree-Fo
ck (HF) and post Hartree-Fock (pHF) calculations, using a sufficiently
large basis set, lead to results that are qualitatively similar. Howe
ver, local density functional (LDF) calculations produce results that
are not compatible. The resulting barrier heights vary from 2.36 (LDF)
to 12.76 kcal/mol (MP4SDTQ/6-31G) passing through a value of 8.33 kc
al/mol from a HF/6-31 G calculation. It is concluded that the LDF resu
lts, within the approximations used in that calculation, appear to be
anomalous when compared to the HF and pHF results.