Ab initio propagator analysis of the valence double-ionization spectra of propyne

Abstract

Double-ionization energies, for transitions from the ground state of the neutral propyne molecule to both singlet and triplet states of its dication, are investigated theoretically with the ab initio second-order algebraic diagrammatic construction [ADC(2)] propagator method. The results are compared with a previous study which reported both experimental data obtained from double-charge-transfer (DCT) spectroscopy and their analysis with semiempirical theory. The ADC(2) predictions match almost all the experimental peaks well. In the lower-energy range, for transitions to dication states up to 7 eV above the ground state, ADC(2) predictions indicate that significant energy separations of those dication terms dominated by a common electronic configuration are responsible for previous difficulties in the assignment of peaks in that region. At higher energies, both configuration interaction and satellite ionizations are significant. © 1997 John Wiley & Sons, Inc. Int J Quant Chem 64: 175–182, 1997