title: Titanium Digermanium: Theoretical Assignment of Electronic Transitions Underlying Its Anion Photoelectron Spectrum.
abstract: Electronic structures of both the anionic and neutral triatomic species TiGe2-/0were theoretically studied employing single-reference (DFT and RCCSD(T)) and multiconfigurational (CASSCF/CASPT2 and CASSCF/NEVPT2) methods with large basis sets. The ground state of TiGe2-(C2v) was identified to be4B1, but the2A1state is nearly degenerate, whereas the3B1is clearly the ground state of the neutral TiGe2(C2v). On the basis of the computed ground and excited states of both neutral and anionic structures, all electronic transitions giving rise to experimental anion photoelectron bands in the spectrum of TiGe2-can now be assigned. The X band of the anion photoelectron spectrum is attributed to a one-electron transition between two ground states4B1→3B1. Three neutral excited states 23A2, 25B1, and 35B1are energetically responsible for the B band upon one-electron photodetachement from the anionic ground state4B1. The C band is assigned to the transition4B1→ 25A1. A transition from the nearly degenerate ground state2A1of the anion to the low-spin1A1of the final neutral state can be ascribed to the A band. Furthermore, the first two bands' progressions, whose normal vibrational modes were accessible from CASSCF/CASPT2 calculations, were also simulated by determination of multidimensional Franck-Condon factors.
authors.affiliation: Department of Chemistry, KU Leuven , Celestijnenlaan 200F, B-3001 Leuven, Belgium.
authors.forename: Le Nhan
authors.initials: LN
authors.lastname: Pham
authors.affiliation: Computational Chemistry Research Group, Ton Duc Thang University , Ho Chi Minh City, 778000 Vietnam.|Faculty of Applied Sciences, Ton Duc Thang University , Ho Chi Minh City, 778000 Vietnam.|Department of Chemistry, KU Leuven , Celestijnenlaan 200F, B-3001 Leuven, Belgium.
authors.forename: Minh Tho
authors.identifier: http://orcid.org/0000-0002-3803-0569
authors.initials: MT
authors.lastname: Nguyen