Study of the low-lying states of Ge2 and Ge−2 using negative ion zero electron kinetic energy spectroscopy

Abstract

Electronenergyloss spectroscopy of condensed butadiene and cyclopentadiene: Vibrationally resolved excitation of the lowlying triplet states J. Chem. Phys. 98, 8397 (1993); 10.1063/1.464498Study of the lowlying electronic states of Si2 and Si− 2 using negative ion photodetachment techniques A study of the lowlying electronic states of Fe2 and Co2 by negative ion photoelectron spectroscopyThe low-lying states of Ge 2 and Ge 2Ϫ are probed using negative ion zero electron kinetic energy ͑ZEKE͒ spectroscopy. The ZEKE spectrum of Ge 2Ϫ yields an electron affinity of 2.035Ϯ0.001 eV for Ge 2 , as well as term energies and vibrational frequencies for the low-lying states of Ge 2Ϫ and Ge 2 . Specifically, we observe transitions originating from the anion 2 ⌸ u ͑3/2͒ ground state and 3 ⌺ g ϩ excited state ͑T e ϭ279Ϯ10 cm Ϫ1 ͒ to several triplet and singlet states of Ge 2 . Term values and vibrational frequencies are determined for the Ge 2 3 ⌺ g ϩ ground state, the low-lying 3 ⌸ u excited state ͑T e ϭ337 cm Ϫ1 for the 2 u spin-orbit component͒, and the somewhat higher lying 1 ⌬ g , 3 ⌺ g ϩ , and 1 ⌸ u states. We also determine the zero-field splitting for the X0 g ϩ and 1 g components of the 3 ⌺ g ϩ state and the splittings between the 2 u , 1 u , and 0 u Ϯ spin-orbit components of the 3 ⌸ u state. Detailed comparisons are made with Si 2 and Si 2Ϫ .

Titanium Digermanium: Theoretical Assignment of Electronic Transitions Underlying Its Anion Photoelectron Spectrum

“…Formal oxidation states can be inferred by considering the electronic structures of Ge 2 – and TiGe 2 – . Although there are still arguments over the electronic ground state of Ge 2 – , the two lowest-lying states are theoretically and experimentally established as nearly degenerate. − Both states 2 Π u [...2σ g 2 2π u 3 ] and 2 Σ g + [...2σ g 1 2π u 4 ] have one singly occupied orbital and can combine with titanium atoms to form TiGe 2 – . By comparing the leading orbital configurations of two lowest nearly degenerate states 4 B 1 and 2 A 1 of the triatomic species with that of Ge 2 – , one can recognize that the singly occupied orbital (π u and/or σ g ) of the Ge 2 – moiety becomes doubly occupied in TiGe 2 – , which means that one electron is actually transferred from titanium to the Ge 2 moiety.…”

N‐Heterocyclic Carbene Stabilized Digermanium(0)

“…The electronic reference state for the diamagnetic complex is the 1 D g excited state (Figure 3 b), which is only 9.5 kcal mol À1 higher in energy. [26] The orbital occupation of the latter state is perfectly suited for donor-acceptor interactions with two NHC ligands. Figure 3 c shows that the vacant p-bonding orbital of the 1 D g state of Ge 2 can serve as an acceptor orbital for donation from the minus combination of the carbon lonepair orbitals of the NHC ligands (b u symmetry in C 2h ), while the associated p* antibonding MO (Figure 3 d) is available as an acceptor orbital for electron donation from the plus combination of the NHC donor orbitals (a g symmetry).…”

Theoretical studies on singlet and triplet states of Ge2

“…0.04 2.33 313 [8] 0.06 2.38 195 [10] 0.08 2.32 278 [7] 0.10 2.34 251 [11] 0.08 2.37 297 Exp. [5] 0.11 *** 308 Exp. [1] 0.09 *** 308 Theoretical studies on singlet and triplet states of Ge 2 3259 Figure 7.…”

“…Negative ion zero electron kinetic energy (ZEKE) experiments on the Ge À 2 ! Ge 2 system by Arnold et al [5] resulted in spectroscopic constants for X 3 AE À g and 1 3 Å u , as well as for some low-lying singlet states. This, and another ZEKE study by Burton et al [6], confirmed 3 AE À g to be the ground state.…”