title: EOMCC, MRPT, and TDDFT studies of charge transfer processes in mixed-valence compounds: application to the spiro molecule.
abstract: The proper description of electron transfer (ET) processes in mixed-valence compounds poses a significant challenge for commonly used theoretical approaches. In this paper we analyze the 1(2)A(2) and 2(2)A(2) potential energy surfaces of the Spiro cation (5,5'(4H,4H')-spirobi[cyclopenta[c]pyrrole]2,2',6,6'-tetrahydro cation) which is a frequently used model to study ET processes. We compare and contrast the results obtained with three different methods: multireference perturbation theory, equation-of-motion coupled cluster theory, time-dependent density functional theory. We demonstrate that the proper inclusion of dynamical correlation effects plays a crucial role in the description of an avoided crossing between potential energy surfaces. We also find that proper balancing of the ground- and excited-state correlation effects is especially challenging in the vicinity of the 1(2)A(2) and 2(2)A(2) avoided crossing region.
authors.affiliation: William R. Wiley Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, Washington 99352 USA.
authors.forename: Kurt R
authors.initials: KR
authors.lastname: Glaesemann
authors.forename: Niranjan
authors.initials: N
authors.lastname: Govind
authors.forename: Sriram
authors.initials: S
authors.lastname: Krishnamoorthy
authors.forename: Karol
authors.initials: K
authors.lastname: Kowalski
mesh_terms: D004583:Electrons; D056004:Molecular Dynamics Simulation; D011789:Quantum Theory; D013141:Spiro Compounds / Q000737:chemistry*
chemical_list: D013141:Spiro Compounds