IS ACETYLENE RADICAL-ANION WITH A TRANS-BENT FORM OBSERVED IN MATRIX EXPERIMENT - AN AB-INITIO STUDY

Based on extensive ab initio calculations of the hyperfine coupling co nstants of both hydrogen and carbon nuclei of three C2H2- anions, it i s confirmed that an acetylene radical anion has effectively been produ ced radiolytically in low temperature alkane matrices and it possesses a trans-bent form. The results are derived from different molecular o rbital configuration interaction calculations (CIS, CISD, QCISD and MR D-CI) as well as density functional theory (DFT) employing extended ba sis sets. Both popular DFT methods (BLYP and B3LYP) show some difficul ties in calculating the isotropic coupling constants of the carbon nuc lei. (C) 1996 American Institute of Physics.