title: Ground and excited states of the diatomic dianion Cl2(2-).
abstract: The QCISD(T)/aug-cc-pVQZ and CIS/aug-cc-pVQZ calculations have been carried out to obtain potential energy curves (PECs) of the Cl2(2-) diatomic dianion in order to address possibility of its formation in the merged beam fragmentation of Cl2(-) questioned based on the observation of the Cl(-)+Cl+e(-) channel. Results show that two of the excited states, namely A(1)Σg and a(3)Σg are metastable with PECs having wells deep enough to suite several bound states, with minima located at Re=2.8280 Å and Re=2.5972 Å, and Coulomb barriers of 1648.288 and 1403.835 cm(-1) heights located at 4.0320 and 3.6130 Å, respectively. Transition probabilities and tunneling predissociation lifetimes corresponding to these metastable states are also calculated and analyzed. Ground state X(1)Σg and excited states B(1)Σu, C(1)Πg and D(1)Πu calculated for this dianion are all repulsive. Calculated Franck-Condon factors suggest that Cl2(2-) can be produced in its excited states via an electron impact process initiating from the ground states of Cl2 and Cl2(-) .
authors.affiliation: Department of Chemistry, University of Isfahan, Isfahan 81746-73441, Islamic Republic of Iran. Electronic address: sabzyan@sci.ui.ac.ir.
authors.forename: Hassan
authors.initials: H
authors.lastname: Sabzyan
authors.forename: Zeinab
authors.initials: Z
authors.lastname: Noorisafa
authors.forename: Elham
authors.initials: E
authors.lastname: Keshavarz
mesh_terms: D000838:Anions / Q000737:chemistry*; D002712:Chlorides / Q000737:chemistry*; D017377:Diatoms / Q000737:chemistry*; D004583:Electrons; D013816:Thermodynamics
chemical_list: D000838:Anions; D002712:Chlorides
keywords: Diatomic dianion; Potential energy curves (PECs); Repulsive Coulomb Barrier (RCB); Spectroscopic properties