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1. Ionization energies and cationic bond dissociation energies of RuB, RhB, OsB, IrB, and PtB

   https://doi.org/10.1063/5.0107086  

   Merriles, Dakota M. ; Morse, Michael D. ( August 2022 , The Journal of Chemical Physics)

   Two-photon ionization thresholds of RuB, RhB, OsB, IrB, and PtB have been measured using resonant two-photon ionization spectroscopy in a jet-cooled molecular beam and have been used to derive the adiabatic ionization energies of these molecules. From the measured two-photon ionization thresholds, IE(RuB) = 7.879(9) eV, IE(RhB) = 8.234(10) eV, IE(OsB) = 7.955(9) eV, IE(IrB) = 8.301(15) eV, and IE(PtB) = 8.524(10) eV have been assigned. By employing a thermochemical cycle, cationic bond dissociation energies of these molecules have also been derived, giving D₀(Ru⁺–B) = 4.297(9) eV, D₀(Rh⁺–B) = 4.477(10) eV, D₀(Os–B⁺) = 4.721(9) eV, D₀(Ir–B⁺) = 4.925(18) eV, and D₀(Pt–B⁺) = 5.009(10) eV. The electronic structures of the resulting cationic transition metal monoborides (MB⁺) have been elucidated using quantum chemical calculations. Periodic trends of the MB⁺molecules and comparisons to their neutral counterparts are discussed. The possibility of quadruple chemical bonds in all of these cationic transition metal monoborides is also discussed.
2. Bond dissociation energies of diatomic transition metal nitrides

   https://doi.org/10.1063/5.0141182  

   Merriles, Dakota M. ; Knapp, Annie S. ; Barrera-Casas, Yexalen ; Sevy, Andrew ; Sorensen, Jason J. ; Morse, Michael D. ( February 2023 , The Journal of Chemical Physics)

   Resonant two-photon ionization (R2PI) spectroscopy has been used to measure the bond dissociation energies (BDEs) of the diatomic transition metal nitrides ScN, TiN, YN, MoN, RuN, RhN, HfN, OsN, and IrN. Of these, the BDEs of only TiN and HfN had been previously measured. Due to the many ways electrons can be distributed among the d orbitals, these molecules possess an extremely high density of electronic states near the ground separated atom limit. Spin–orbit and nonadiabatic interactions couple these states quite effectively, so that the molecules readily find a path to dissociation when excited above the ground separated atom limit. The result is a sharp drop in ion signal in the R2PI spectrum when the molecule is excited above this limit, allowing the BDE to be readily measured. Using this method, the values D₀(ScN) = 3.905(29) eV, D₀(TiN) = 5.000(19) eV, D₀(YN) = 4.125(24) eV, D₀(MoN) = 5.220(4) eV, D₀(RuN) = 4.905(3) eV, D₀(RhN) = 3.659(32) eV, D₀(HfN) = 5.374(4) eV, D₀(OsN) = 5.732(3) eV, and D₀(IrN) = 5.115(4) eV are obtained. To support the experimental findings, ab initio coupled-cluster calculations extrapolated to the complete basis set limit (CBS) were performed. With a semiempirical correction for spin–orbit effects, these coupled-clustermore »single double triple-CBS calculations give a mean absolute deviation from the experimental BDE values of 0.20 eV. A discussion of the periodic trends, summaries of previous work, and comparisons to isoelectronic species is also provided.

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3. Al Composition Dependence of Band Offsets for SiO ₂ on α-(Al _x Ga _1−x ) ₂ O ₃

   https://doi.org/10.1149/2162-8777/ac39a8  

   Xia, Xinyi ; Fares, Chaker ; Ren, Fan ; Hassa, Anna ; von Wenckstern, Holger ; Grundmann, Marius ; Pearton, S. J. ( November 2021 , ECS Journal of Solid State Science and Technology)

   Valence band offsets for SiO 2 deposited by Atomic Layer Deposition on α -(Al x Ga 1-x ) 2 O 3 alloys with x = 0.26–0.74 were measured by X-ray Photoelectron Spectroscopy. The samples were grown with a continuous composition spread to enable investigations of the band alignment as a function of the alloy composition. From measurement of the core levels in the alloys, the bandgaps were determined to range from 5.8 eV (x = 0.26) to 7 eV (x = 0.74). These are consistent with previous measurements by transmission spectroscopy. The valence band offsets of SiO 2 with these alloys of different composition were, respectively, were −1.2 eV for x = 0.26, −0.2 eV for x = 0.42, 0.2 eV for x = 0.58 and 0.4 eV for x = 0.74. All of these band offsets are too low for most device applications. Given the bandgap of the SiO 2 was 8.7 eV, this led to conduction band offsets of 4.1 eV (x = 0.26) to 1.3 eV (x = 0.74). The band alignments were of the desired nested configuration for x > 0.5, but at lower Al contents the conduction band offsets were negative, with a staggered bandmore »alignment. This shows the challenge of finding appropriate dielectrics for this ultra-wide bandgap semiconductor system.« less
4. A Dual-Reporter Platform for Screening Tumor-Targeted Extracellular Vesicles

   https://doi.org/10.3390/pharmaceutics14030475  

   Kanada, Masamitsu ; Linenfelser, Lauren ; Cox, Elyssa ; Gilad, Assaf A. ( March 2022 , Pharmaceutics)

   Extracellular vesicle (EV)-mediated transfer of biomolecules plays an essential role in intercellular communication and may improve targeted drug delivery. In the past decade, various approaches to EV surface modification for targeting specific cells or tissues have been proposed, including genetic engineering of parental cells or postproduction EV engineering. However, due to technical limitations, targeting moieties of engineered EVs have not been thoroughly characterized. Here, we report the bioluminescence resonance energy transfer (BRET) EV reporter, PalmReNL-based dual-reporter platform for characterizing the cellular uptake of tumor-homing peptide (THP)-engineered EVs, targeting PDL1, uPAR, or EGFR proteins expressed in MDA-MB-231 breast cancer cells, simultaneously by bioluminescence measurement and fluorescence microscopy. Bioluminescence analysis of cellular EV uptake revealed the highest binding efficiency of uPAR-targeted EVs, whereas PDL1-targeted EVs showed slower cellular uptake. EVs engineered with two known EGFR-binding peptides via lipid nanoprobes did not increase cellular uptake, indicating that designs of EGFR-binding peptide conjugation to the EV surface are critical for functional EV engineering. Fluorescence analysis of cellular EV uptake allowed us to track individual PalmReNL-EVs bearing THPs in recipient cells. These results demonstrate that the PalmReNL-based EV assay platform can be a foundation for high-throughput screening of tumor-targeted EVs.
5. Laboratory Study of the Cameron Bands, the First Negative Bands, and Fourth Positive Bands in the Middle Ultraviolet 180–280 nm by Electron Impact upon CO

   https://doi.org/https://doi.org/10.1029/2020JE006602  

   Rena A. Lee1, a ( January 2021 , Journal of Geological Research)

   We have analyzed medium-resolution (FWHM = 1.2 nm) Middle UltraViolet (MUV; 180–280 nm) laboratory emission spectra of CO excited by electron impact at 15, 20, 40, 50, and 100 eV under single-scattering conditions at 300 K. The MUV emission spectra at 100 eV contain the Cameron Bands (CB) CO(a 3Π → X 1Σ+), the Fourth Positive Group (4PG) CO(A 1Π → X 1Σ+), and the First Negative Group (1NG) CO+(B 2Σ+ → X 2Σ) from direct excitation and cascading-induced emission of an optically-thin CO gas. We have determined vibrational intensities and emission cross sections for these systems, which are important for modeling UV observations of the atmospheres of Mars and Venus. We have also measured the CB ‘glow’ profile about the electron beam of the long-lived CO (a 3Π) state and determined its average metastable lifetime of approximately 3 ± 1 ms. Optically-allowed cascading from a host of triplet states has been found to be the dominant excitation process contributing to the CB emission cross section at 15 eV, most strongly by the d 3Δ and a' 3Σ+ electronic states. We normalized the CB emission cross section at 15 eV electron impact energy by Multi-Linear Regression (MLR) analysis to themore »blended 15 eV MUV spectrum over the spectral range of 180–280 nm, based on the 4PG emission cross section at 15 eV that we have previously measured (Ajello et al., 2019). We find the Cameron band total emission cross section at 15 eV to be (7.65 ± 2.68) × 10−17 cm2.« less