In:
The Journal of Chemical Physics, AIP Publishing, Vol. 139, No. 17 ( 2013-11-07)
Kurzfassung:
Employing the multi-state multiconfiguration second-order perturbation theory (MS-CASPT2) and complete active space self-consistent field (CASSCF) methods, the geometries, relative energies (Tv′) to the ground state (X3Σg−), adiabatic excited energies, and photodissociation mechanisms and corresponding kinetic energy releases for the lower-lying 14 electronic states of the CO22+ ion are studied. The Tv′ values are calculated at the experimental geometry of the ground state CO2 molecule using MS-CASPT2 method and highly close to the latest threshold photoelectrons coincidence and time-of-flight photoelectron photoelectron coincidence spectrum observations. The O-loss dissociation potential energy curves (PECs) for these 14 states are drawn using MS-CASPT2 partial optimization method at C∞v symmetry with one C–O bond length ranging from 1.05 to 8.0 Å. Those 14 states are confirmed to be correlated to the lowest four dissociation limits [CO+(X2Σ+) + O+(4Su), CO+(A2Π) + O+(4Su), CO+(X2Σ+) + O+(2Du), and CO+(X2Σ+) + O+(2Pu)] by analyzing Coulomb interaction energies, charges, spin densities, and bond lengths for the geometries at the C–O bond length of 8.0 Å. On the basis of these 14 MS-CASPT2 PECs, several state/state pairs are selected to optimize the minimum energy crossing points (MECPs) at the CASSCF level. And then the CASSCF spin-orbit couplings and CASPT2 state/state energies are calculated at these located MECPs. Based on all of the computational results, the photodissociation mechanisms of CO22+ are proposed. The relationships between the present theoretical studies and the previous experiments are discussed.
Materialart:
Online-Ressource
ISSN:
0021-9606
,
1089-7690
Sprache:
Englisch
Verlag:
AIP Publishing
Publikationsdatum:
2013
ZDB Id:
3113-6
ZDB Id:
1473050-9
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