ACCURATE DENSITY-FUNCTIONAL CALCULATION OF CORE ELECTRON-BINDING ENERGIES .5. APPLICATION TO NITRILES - MODEL MOLECULES FOR POLYACRYLONITRILE REVISITED
C. Bureau et al., ACCURATE DENSITY-FUNCTIONAL CALCULATION OF CORE ELECTRON-BINDING ENERGIES .5. APPLICATION TO NITRILES - MODEL MOLECULES FOR POLYACRYLONITRILE REVISITED, Journal of electron spectroscopy and related phenomena, 83(2-3), 1997, pp. 227-234
A recent procedure for computing accurate core electron binding energi
es (CEBEs) via density functional theory (DFT) is applied to acetonitr
ile, propionitrile, 2-cyanopropane, acrylonitrile, methacrylonitrile a
nd the 2-methylglutaronitrile conformer of lowest energy, The first th
ree systems have been studied in the past as model compounds to interp
ret the XPS spectrum of polyacrylonitrile (PAN) using post-Hartree-Foc
k finite-difference calculations, in order to solve a controversy in t
he assignment of chemically shifted atoms in the C 1s region, This ass
ignment is revisited with the unrestricted generalized transition-stat
e model and a combined functional of Becke's 1988 exchange with Perdew
's 1986 correlation. Using Dunning's correlation-consistent polarized
valence triple zeta basis sets with scaling improvements, we obtain pr
edicted CEBEs for gasphase acetonitrile, propionitrile and acrylonitri
le in remarkable agreement with experiment (average absolute deviation
0.09 eV). The CEBEs of these systems confirm the overall trends of th
e previous attributions of their respective gas-phase XPS spectrum, ex
cept in the case of propionitrile. These results, as well as those on
2-cyanopropane, methacrylonitrile and 2-methylglutaronitrile, bring so
me additional information on the extrapolation of the results to the a
ssignment of the C 1s contributions of polyacrylonitrile. (C) 1997 Els
evier Science B.V.