Quantum State-Dependent Fragmentation Dynamics of DS Molecules Following Excitation at Wavelengths ∼ 129.1 and ∼ 139.1 nm.

The first high-resolution translational spectroscopy studies of D atom photoproducts following excitation to the Rydberg states of DS are reported. Excitation at wavelengths λ ∼ 139.1 nm reveals an unusual 'inverse' isotope effect; the B(3←2) Rydberg state of DS predissociates much faster than its counterpart in HS.

Photodissociation dynamics of SO2 via the G̃1B1 state: The O(1D2) and O(1S0) product channels.

Produced by both nature and human activities, sulfur dioxide (SO2) is an important species in the earth's atmosphere. SO2 has also been found in the atmospheres of other planets and satellites in the solar system. The photoabsorption cross sections and photodissociation of SO2 have been studied for several decades.

Unraveling the Rich Fragmentation Dynamics Associated with S-H Bond Fission Following Photoexcitation of HS at Wavelengths ∼129.1 nm.

HS is being detected in the atmospheres of ever more interstellar bodies, and photolysis is an important mechanism by which it is processed. Here, we report H Rydberg atom time-of-flight measurements following the excitation of HS molecules to selected rotational (') levels of the B Rydberg state associated with the strong absorption feature at wavelengths of λ ∼ 129.1 nm.

Roaming in highly excited states: The central atom elimination of triatomic molecule decomposition.

Chemical reactions are generally assumed to proceed from reactants to products along the minimum energy path (MEP). However, straying from the MEP-roaming-has been recognized as an unconventional reaction mechanism and found to occur in both the ground and first excited states. Its existence in highly excited states is however not yet established.

Development of stapled NONO-associated peptides reveals unexpected cell permeability and nuclear localisation.

The non-POU domain-containing octamer-binding protein (NONO) is a nucleic acid-binding protein with diverse functions that has been identified as a potential cancer target in cell biology studies. Little is known about structural motifs that mediate binding to NONO apart from its ability to form homodimers, as well as heterodimers and oligomers with related homologues. We report a stapling approach to macrocyclise helical peptides derived from the insulin-like growth factor binding protein (IGFBP-3) that NONO interacts with, and also from the dimerisation domain of NONO itself.

Vacuum ultraviolet photodissociation of sulfur dioxide and its implications for oxygen production in the early Earth's atmosphere.

The emergence of molecular oxygen (O) in the Earth's primitive atmosphere is an issue of major interest. Although the biological processes leading to its accumulation in the Earth's atmosphere are well understood, its abiotic source is still not fully established. Here, we report a new direct dissociation channel yielding S(D) + O(aΔ/XΣ) products from vacuum ultraviolet (VUV) photodissociation of SO in the wavelength range between 120 and 160 nm.

Photodissociation dynamics of SO2 between 193 and 201 nm.

The nonadiabatic interactions between the C̃ state and neighboring electronic states of SO2 have attracted much attention; however, the predissociation mechanisms are not yet completely understood. In this work, the predissociation dynamics of SO2 via its C̃ state have been investigated at λ = 193-201 nm by using the time-sliced velocity map ion imaging technique. The translational energy distributions and the branching ratios of the O(3PJ=2,1,0) spin-orbit products at six photolysis wavelengths have been acquired.

Slice imaging study of NO photodissociation the 1B and 2B states: the NO(XΠ) + O(P) product channel.

The state-resolved photodissociation of NO the 1B and 2B excited states has been investigated by using time-sliced velocity-mapped ion imaging technique. The images of the O(P) products at a series of excitation wavelengths are measured by employing a 1 + 1' photoionization scheme. The total kinetic energy release (TKER) spectra, NO vibrational state distributions and anisotropy parameters () are derived from the O(P) images.

Modeling of and Experimenting with Concentric Tube Robots: Considering Clearance, Friction and Torsion.

Concentric tube robots (CTRs) are a promising prospect for minimally invasive surgery due to their inherent compliance and ability to navigate in constrained environments. Existing mechanics-based kinematic models typically neglect friction, clearance, and torsion between each pair of contacting tubes, leading to large positioning errors in medical applications. In this paper, an improved kinematic modeling method is developed.

The vibronic state dependent predissociation of HS: determination of all fragmentation processes.

Photochemistry plays a significant role in shaping the chemical reaction network in the solar nebula and interstellar clouds. However, even in a simple triatomic molecule photodissociation, determination of all fragmentation processes is yet to be achieved. In this work, we present a comprehensive study of the photochemistry of HS, derived from cutting-edge translational spectroscopy measurements of the H, S(D) and S(S) atom products formed by photolysis at wavelengths across the range 155-120 nm.

Catalyst-Support Interactions Promoted Acidic Electrochemical Oxygen Evolution Catalysis: A Mini Review.

In the context of the growing human demand for green secondary energy sources, proton-exchange membrane water electrolysis (PEMWE) is necessary to meet the high-efficiency production of high-purity hydrogen required for proton-exchange membrane fuel cells (PEMFCs). The development of stable, efficient, and low-cost oxygen evolution reaction (OER) catalysts is key to promoting the large-scale application of hydrogen production by PEMWE. At present, precious metals remain irreplaceable in acidic OER catalysis, and loading the support body with precious metal components is undoubtedly an effective strategy to reduce costs.

Photodissociation of HS: A New Pathway for the Production of Vibrationally Excited Molecular Hydrogen in the Interstellar Medium.

Hydrogen sulfide (HS) is the most abundant S-bearing molecule in the solar nebula. Although its photochemistry has been studied for decades, the H fragment channel is still not well-understood. Herein, we describe the photodissociation dynamics of HS + → S(S) + H(XΣ) with the excitation wavelength of 122 nm ≤ λ ≤ 136 nm.

Polymeric Amines Induce Nitric Oxide Release from S-Nitrosothiols.

Catalytic generation of nitric oxide (NO) from NO donors by nanomaterials has enabled prolonged NO delivery for various biomedical applications, but this approach requires laborious synthesis routes. In this study, a new class of materials, that is, polymeric amines including polyethyleneimine (PEI), poly-L-lysine, and poly(allylamine hydrochloride), is discovered to induce NO generation from S-nitrosothiols (RSNOs) at physiological conditions. Controlled NO generation can be readily achieved by tuning the concentration of the NO donors (RSNOs) and polymers, and the type and molecular weight of the polymers.

Rotational state specific dissociation dynamics of DO via the C̃(010) state: The effect of bending vibrational excitation.

The rotational state resolved photodissociation dynamics of DO via the C̃(010) state has been investigated by using the D-atom Rydberg tagging time-of-flight technique combined with a tunable vacuum ultraviolet light source. The D-atom action spectrum of the C̃(010) ← X̃(000) band and the corresponding time-of-flight (TOF) spectra of D-atom photoproducts formed following the excitation of DO to individual rotational transition have been measured. By comparison with the action spectrum of the C̃(000) ← X̃(000) band, the bending vibrational constant of the C̃ state for DO can be determined to be v = 1041.

Photodissociation dynamics of CO + hv → CO(XΣ) + O(D) via the 3PΠ state.

The vacuum ultraviolet (VUV) photodissociation of CO is important to understand the primary photochemical processes of CO induced by solar VUV excitation in the Earth's atmosphere. Here, we report a detailed study of vibrational-state-specific photodissociation dynamics of the CO(XΣ) + O(D) channel via the 3PΠ state by using the time-sliced velocity-mapped ion imaging apparatus combined with the single VUV photoionization detection scheme. By recording the sliced images of the O(D) photoproducts formed by VUV photoexcitation of CO to the individual vibrational structure of the 3PΠ state, both the vibrational state distributions of the counterpart CO(XΣ) photoproducts and the vibrational-state-specific product anisotropy parameters (β) are determined.

Ceria Nanoparticles as an Unexpected Catalyst to Generate Nitric Oxide from S-Nitrosoglutathione.

Ceria nanoparticles (NPs) are widely reported to scavenge nitric oxide (NO) radicals. This study reveals evidence that an opposite effect of ceria NPs exists, that is, to induce NO generation. Herein, S-nitrosoglutathione (GSNO), one of the most biologically abundant NO donors, is catalytically decomposed by ceria NPs to produce NO.

Rotational and nuclear-spin level dependent photodissociation dynamics of HS.

The detailed features of molecular photochemistry are key to understanding chemical processes enabled by non-adiabatic transitions between potential energy surfaces. But even in a small molecule like hydrogen sulphide (HS), the influence of non-adiabatic transitions is not yet well understood. Here we report high resolution translational spectroscopy measurements of the H and S(D) photoproducts formed following excitation of HS to selected quantum levels of a Rydberg state with B electronic symmetry at wavelengths λ ~ 139.

Strong isotope effect in the VUV photodissociation of HOD: A possible origin of D/H isotope heterogeneity in the solar nebula.

The deuterium versus hydrogen (D/H) isotopic ratios are important to understand the source of water on Earth and other terrestrial planets. However, the determinations of D/H ratios suggest a hydrogen isotopic diversity in the planetary objects of the solar system. Photochemistry has been suggested as one source of this isotope heterogeneity.

Three body photodissociation of the water molecule and its implications for prebiotic oxygen production.

The provenance of oxygen on the Earth and other planets in the Solar System is a fundamental issue. It has been widely accepted that the only prebiotic pathway to produce oxygen in the Earth's primitive atmosphere was via vacuum ultraviolet (VUV) photodissociation of CO and subsequent two O atom recombination. Here, we provide experimental evidence of three-body dissociation (TBD) of HO to produce O atoms in both D and P states upon VUV excitation using a tunable VUV free electron laser.

Photodissociation Dynamics of HO via the ' (B) Electronic State.

Photodissociation dynamics of HO via the 'B state were studied using the high-resolution H atom photofragment translational spectroscopy method, in combination with the tunable vacuum ultraviolet free electron laser (VUV FEL). The measured translational energy spectra allow us to determine the respective quantum state population distributions for the nascent OH(XΠ) and OH(AΣ) photofragments. Analyses of the quantum state population distributions show both the ground and electronically excited OH fragments to be formed with moderate vibrational excitation but with highly rotational excitation.

Direct Observation of the C + S Channel in CS Photodissociation.

Carbon disulfide (CS) is a typical triatomic molecule. Its photodissociation process has generally been assumed to proceed to CS and S primary products via single bond fission. However, recent theoretical calculations suggested that an exit channel to produce C + S should also be energetically accessible.

Water Photolysis and Its Contributions to the Hydroxyl Dayglow Emissions in the Atmospheres of Earth and Mars.

Airglow is a well-known phenomenon in the Earth's upper atmosphere, which arises from the emissions of energetic atoms and molecules. The Meinel band emission from high vibrationally excited OH(X) radicals is one of the more important contributors to the airglow from the mesosphere/lower thermosphere. The H + O reaction has long been regarded as the dominant source of these OH(X, high ) radicals.

Electronically Excited OH Super-rotors from Water Photodissociation by Using Vacuum Ultraviolet Free-Electron Laser Pulses.

The fragmentation dynamics of water in a superexcited state play an important role in the ionosphere of the planets and in the photodissociation region (PDR) of the planetary nebula. In this Letter, we experimentally study the fragmentation dynamics of HO with the energy above its ionization potential initiated by vacuum ultraviolet free-electron laser pulses. The experimental results indicate that the binary fragmentation channels H + OH and the triple channels O + 2H both present at 96.

State-to-state photodissociation dynamics of CO around 108 nm: the O(S) atom channel.

State-to-state photodissociation of carbon dioxide (CO2) via the 3p1Πu Rydberg state was investigated by the time-sliced velocity map ion imaging technique (TSVMI) using a tunable vacuum ultraviolet free electron laser (VUV FEL) source. Raw images of the O(1S) products resulting from the O(1S) + CO(X1Σ+) channel were acquired at the photolysis wavelengths between 107.37 and 108.