On the discrepancy between theory and experiment for the F-F spin-spin coupling constant of difluoethyne
Research output: Contribution to journal › Journal article › Research › peer-review
Standard
On the discrepancy between theory and experiment for the F-F spin-spin coupling constant of difluoethyne. / Faber, Rasmus; Sauer, Stephan P. A.
In: Physical Chemistry Chemical Physics, Vol. 14, No. 47, 2012, p. 16440-16447.Research output: Contribution to journal › Journal article › Research › peer-review
Harvard
APA
Vancouver
Author
Bibtex
}
RIS
TY - JOUR
T1 - On the discrepancy between theory and experiment for the F-F spin-spin coupling constant of difluoethyne
AU - Faber, Rasmus
AU - Sauer, Stephan P. A.
PY - 2012
Y1 - 2012
N2 - The vicinal indirect nuclear spin-spin coupling constant (SSCC) between the two ¿uorine atoms in di¿uoroethyne has been reinvestigated. This coupling has previously proved dif¿cult to calculate accurately. In this study we have therefore systematically investigated the dependence of this coupling on the choice of one-electron basis set, the choice of correlated wave function method and the inclusion of zero-point vibrational and temperature corrections. All terms of the SSCC have been evaluated at the second-order polarization propagator, SOPPA and SOPPA(CCSD), and coupled cluster singles and doubles (CCSD) levels of theory and for the most correlation dependent term, the paramagnetic spin-orbit contribution (PSO), also at the very accurate CC3 level. We ¿nd that in order to get results that are well converged with respect to the basis set, one needs to use special SSCC optimized basis sets of at least quadruple zeta quality and with added diffuse functions. Furthermore, the PSO term is not yet converged at the CCSD level as shown by the CC3 calculations. Finally, it is shown that vibrational effects are very important, as they are in this case of the same order of magnitude as the equilibrium geometry value of the coupling constant. Only by using a converged basis set and including both vibrational and higher order correlation effects can we obtain agreement with the experimental value for this coupling.
AB - The vicinal indirect nuclear spin-spin coupling constant (SSCC) between the two ¿uorine atoms in di¿uoroethyne has been reinvestigated. This coupling has previously proved dif¿cult to calculate accurately. In this study we have therefore systematically investigated the dependence of this coupling on the choice of one-electron basis set, the choice of correlated wave function method and the inclusion of zero-point vibrational and temperature corrections. All terms of the SSCC have been evaluated at the second-order polarization propagator, SOPPA and SOPPA(CCSD), and coupled cluster singles and doubles (CCSD) levels of theory and for the most correlation dependent term, the paramagnetic spin-orbit contribution (PSO), also at the very accurate CC3 level. We ¿nd that in order to get results that are well converged with respect to the basis set, one needs to use special SSCC optimized basis sets of at least quadruple zeta quality and with added diffuse functions. Furthermore, the PSO term is not yet converged at the CCSD level as shown by the CC3 calculations. Finally, it is shown that vibrational effects are very important, as they are in this case of the same order of magnitude as the equilibrium geometry value of the coupling constant. Only by using a converged basis set and including both vibrational and higher order correlation effects can we obtain agreement with the experimental value for this coupling.
KW - Faculty of Science
KW - NMR
KW - spin-spin coupling constants
KW - difluoroethyne
KW - vibrational correction
KW - quantum chemistry
KW - Computational Chemistry
U2 - 10.1039/C2CP42198D
DO - 10.1039/C2CP42198D
M3 - Journal article
VL - 14
SP - 16440
EP - 16447
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 47
ER -
ID: 40861618