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1. First detection and analysis of an electronic spectrum of vanadium hydride: The D ⁵ Π –X ⁵ Δ (0,0) band

   https://doi.org/10.1063/5.0105844  

   Varberg, Thomas D. (August 2022, The Journal of Chemical Physics)

   The D 5 Π–X 5 Δ (0,0) band of vanadium hydride at 654 nm has been recorded by laser excitation spectroscopy and represents the first analyzed spectrum of VH in the gas phase. The molecules were generated using a hollow cathode discharge source, with laser-induced fluorescence detected via the D 5 Π–A 5 Π (0,0) transition. All five main (ΔΩ = ΔΛ) subbands were observed as well as several satellite ones, which together create a rather complex and overlapped spectrum covering the region 15 180–15 500 cm −1 . The D 5 Π state displays the effects of three strong local perturbations, which are likely caused by interactions with high vibrational levels of the B 5 Σ − and c 3 Σ − states, identified in a previous multiconfigurational self-consistent field study by Koseki et al. [J. Phys. Chem. A 108, 4707 (2004)]. Molecular constants describing the X 5 Δ, A 5 Π, and D 5 Π states were determined in three separate least-squares fits using effective Hamiltonians written in a Hund’s case (a) basis. The fine structure of the ground state is found to be consistent with its assignment as a σπ 2 δ, 5 Δ electronic state. The fitted values of its first-order spin–orbit and rotational constants in the ground state are [Formula: see text] and B = 5.7579(13) cm −1 , the latter of which yields a bond length of [Formula: see text] Å. This experimental value is in good agreement with previous computational studies of the molecule and fits well within the overall trend of decreasing bond length across the series of 3d transition metal monohydrides. 

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2. B ₃₁ ⁻ and B ₃₂ ⁻ : chiral quasi-planar boron clusters

   https://doi.org/10.1039/C9NR01524H  

   Chen, Qiang; Chen, Teng-Teng; Li, Hai-Ru; Zhao, Xiao-Yun; Chen, Wei-Jia; Zhai, Hua-Jin; Li, Si-Dian; Wang, Lai-Sheng (May 2019, Nanoscale)

   Chirality plays an important role in nature. Nanoclusters can also exhibit chiral properties. We report herein a joint experimental and theoretical investigation on the geometric and electronic structures of B 31 − and B 32 − clusters, using photoelectron spectroscopy in combination with first-principles calculations. Two degenerate quasi-planar chiral C 1 enantiomers ( I and II , 1 A) with a central hexagonal vacancy are identified as the global minima of B 31 − . For B 32 − , two degenerate boat-like quasi-planar chiral C 2 structures ( VI and VII , 2 A) with a central hexagonal vacancy are also found as the global minima, with a low-lying chair-like C i B 32 − ( VIII , 2 A u ) also present in the experiment as a minor isomer. The chiral conversions in quasi-planar B 31 − and B 32 − clusters are investigated and relatively low barriers are found due to the high flexibility of these monolayer clusters, which feature multiple delocalized σ and π bonds over buckled molecular surfaces. 

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3. Planar B ₄₁ ⁻ and B ₄₂ ⁻ clusters with double-hexagonal vacancies

   https://doi.org/10.1039/C9NR09522E  

   Bai, Hui; Chen, Teng-Teng; Chen, Qiang; Zhao, Xiao-Yun; Zhang, Yang-Yang; Chen, Wei-Jia; Li, Wan-Lu; Cheung, Ling Fung; Bai, Bing; Cavanagh, Joseph; et al (December 2019, Nanoscale)

   Since the discovery of the B 40 borospherene, research interests have been directed to the structural evolution of even larger boron clusters. An interesting question concerns if the borospherene cages persist in larger boron clusters like the fullerenes. Here we report a photoelectron spectroscopy (PES) and computational study on the structures and bonding of B 41 − and B 42 − , the largest boron clusters characterized experimentally thus far. The PE spectra of both clusters display broad and complicated features, suggesting the existence of multiple low-lying isomers. Global minimum searches for B 41 − reveal three low-lying isomers ( I–III ), which are all related to the planar B 40 − structure. Isomer II ( C s , 1 A′) possessing a double hexagonal vacancy is found to agree well with the experiment, while isomers I ( C s , 3 A′′) and III ( C s , 1 A′) both with a single hexagonal vacancy are also present as minor isomers in the experiment. The potential landscape of B 42 − is found to be much more complicated with numerous low-lying isomers ( VII–XII ). The quasi-planar structure VIII ( C 1 , 2 A) containing a double hexagonal vacancy is found to make major contributions to the observed PE spectrum of B 42 − , while the other low-lying isomers may also be present to give rise to a complicated spectral pattern. Chemical bonding analyses show isomer II of B 41 − ( C s , 1 A′) and isomer VIII of B 42 − ( C 1 , 2 A) are π aromatic, analogous to that in the polycyclic aromatic hydrocarbon C 27 H 13 + ( C 2v , 1 A 1 ). Borospherene cage isomers are also found for both B 41 − and B 42 − in the global minimum searches, but they are much higher energy isomers. 

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4. Synthesis and Reactivity of Functionalized Dimethylgermyl Complexes of the Formula (η ⁵ -C ₅ H ₅ )Re(NO)(PPh ₃ )(GeMe ₂ X); Equilibria Involving the Dimethylgermylene Complex [(η ⁵ -C ₅ H ₅ )Re(NO)(PPh ₃ )(=GeMe ₂ )]• TfO ⁻

   https://doi.org/10.1080/10426509408037445  

   Lee, Kenneth E.; Gladysz, J. A. (February 1994, Phosphorus, Sulfur, and Silicon and the Related Elements)
5. The Role of Tunneling in the Spectra of H ₅ ⁺ and D ₅ ⁺ up to 7300 cm ^-1

   https://doi.org/10.1021/acs.jpca.0c02299  

   Boyer, Mark A.; Chiu, Chloe S.; McDonald, David C.; Wagner, J. Philipp; Colley, Jason E.; Orr, Dylan S.; Duncan, Michael A.; McCoy, Anne B. (May 2020, The Journal of Physical Chemistry A)

   The spectra for H5+ and D5+ are extended to cover the region between 4830 and 7300 cm−1. These spectra are obtained using mass-selected photodissociation spectroscopy. To understand the nature of the states that are accessed by the transitions in this and prior studies, we develop a four-dimensional model Hamiltonian. This Hamiltonian is expressed in terms of the two outer H2 stretches, the displacement of the shared proton from the center of mass of these two H2 groups, and the distance between the H2 groups. This choice is motivated by the large oscillator strength associated with the shared proton stretch and the fact that the spectral regions that have been probed correspond to zero, one, and two quanta of excitation in the H2 stretches. This model is analyzed using an adiabatic separation of the H2 stretches from the other two vibrations and includes the non-adiabatic couplings between H2 stretch states with the same number of quanta of excitation in the H2 stretches. Based on the analysis of the energies and wave functions obtained from this model, we find that when there are one or more quanta of excitation in the H2 stretches the states come in pairs that reflect tunneling doublets. The states accessed by the transitions in the spectrum with the largest intensity are assigned to the members of the doublets with requisite symmetry that are localized on the lowest-energy adiabat for a given level of H2 excitation. 

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