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Updated: Jul 8, 2026

Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
An ab initio study of the vibronic structure in the a1Delta g electronic state of C2H2++
M Perić1, J Palaudoux, M Hochlaf
1Faculty of Physical Chemistry, University of Belgrade, Studentski trg 12, 11000 Belgrade, Serbia. peric@ffh.bg.ac.yu
Abstract:
The results of an ab initio study of the vibronic structure in the a1Deltag electronic state of C2H2++ and its deuterated species (C2D2++) are presented. They are generated employing a simple model that incorporates the minimal number of terms contributing to the Renner-Teller effect. The trans- and cis-bending potential curves at planar nuclear arrangements are obtained by means of large-scale configuration interaction calculations. The corresponding harmonic vibrational frequencies are 717 and 650 cm-1 for C2H2++, and 549 and 477 cm-1 in the case of C2D2++. It is found that the splitting of the potential surfaces is moderate at trans-distortions of linearity, while it is extremely small at cis-bending vibrations. The eigenvalues and eigenfunctions of the model Hamiltonian employed are obtained by means of a perturbative and a variational approach.
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