Browse
Submit Data
Databases
API
Help

Dataset Information

12 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Toward Detection of FeH⁺ in the Interstellar Medium: Infrared Multiple Photon Dissociation Spectroscopy of Ar₂FeH.

ABSTRACT: The iron hydride molecular cation FeH⁺ is expected to be present in the interstellar medium. Because of the lack of laboratory data, it is yet to be identified in spectrally resolved astronomic observations. As a benchmark for computational predictions and to guide an experimental search for the ro-vibrational lines of FeH⁺, we performed infrared multiple photon dissociation (IRMPD) spectroscopy of FeH⁺ tagged with two argon atoms. The Fe-H stretching mode in Ar₂FeH⁺ is observed at 1860 cm^-1. Combination bands of the Fe-H stretch with the two Fe-H bending and the asymmetric Fe-Ar stretching modes are observed at 2012 cm^-1, 2054 cm^-1, and 2078 cm^-1. Quantum chemical calculations show that the molecule has C_2v symmetry. The Ar-Fe-Ar bending mode at 46 cm^-1 is significantly populated at the temperature of the experiment, causing thermal broadening of the Fe-H stretch and its redshift with increasing internal energy.

SUBMITTER: Jin S

PROVIDER: S-EPMC9251756 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

Infrared Multiple Photon Dissociation Spectroscopy of Hydrated Cobalt Anions Doped with Carbon Dioxide CoCO2 (H2 O)n - , n=1-10, in the C-O Stretch Region.

Project description:We investigate anionic [Co,CO2 ,nH2 O]- clusters as model systems for the electrochemical activation of CO2 by infrared multiple photon dissociation (IRMPD) spectroscopy in the range of 1250-2234 cm-1 using an FT-ICR mass spectrometer. We show that both CO2 and H2 O are activated in a significant fraction of the [Co,CO2 ,H2 O]- clusters since it dissociates by CO loss, and the IR spectrum exhibits the characteristic C-O stretching frequency. About 25 % of the ion population can be dissociated by pumping the C-O stretching mode. With the help of quantum chemical calculations, we assign the structure of this ion as Co(CO)(OH)2 - . However, calculations find Co(HCOO)(OH)- as the global minimum, which is stable against IRMPD under the conditions of our experiment. Weak features around 1590-1730 cm-1 are most likely due to higher lying isomers of the composition Co(HOCO)(OH)- . Upon additional hydration, all species [Co,CO2 ,nH2 O]- , n≥2, undergo IRMPD through loss of H2 O molecules as a relatively weakly bound messenger. The main spectral features are the C-O stretching mode of the CO ligand around 1900 cm-1 , the water bending mode mixed with the antisymmetric C-O stretching mode of the HCOO- ligand around 1580-1730 cm-1 , and the symmetric C-O stretching mode of the HCOO- ligand around 1300 cm-1 . A weak feature above 2000 cm-1 is assigned to water combination bands. The spectral assignment clearly indicates the presence of at least two distinct isomers for n ≥2.

| S-EPMC7051846 | biostudies-literature

Size-dependent H and H2 formation by infrared multiple photon dissociation spectroscopy of hydrated vanadium cations, V+(H2O)n, n = 3-51.

Project description:Infrared spectra of the hydrated vanadium cation (V+(H2O)n; n = 3-51) were measured in the O-H stretching region employing infrared multiple photon dissociation (IRMPD) spectroscopy. Spectral fingerprints, along with size-dependent fragmentation channels, were observed and rationalized by comparing to spectra simulated using density functional theory. Photodissociation leading to water loss was found for cluster sizes n = 3-7, consistent with isomers featuring intact water ligands. Loss of molecular hydrogen was observed as a weak channel starting at n = 8, indicating the advent of inserted isomers, HVOH+(H2O)n-1. The majority of ions for n = 8, however, are composed of two-dimensional intact isomers, concordant with previous infrared studies on hydrated vanadium. A third channel, loss of atomic hydrogen, is observed weakly for n = 9-11, coinciding with the point at which the H and H2O calculated binding energies become energetically competitive for intact isomers. A clear and sudden spectral pattern and fragmentation channel intensity at n = 12 suggest a structural change to inserted isomers. The H2 channel intensity decreases sharply and is not observed for n = 20 and 25-51. IRMPD spectra for clusters sizes n = 15-51 are qualitatively similar indicating no significant structural changes, and are thought to be composed of inserted isomers, consistent with recent electronic spectroscopy experiments.

| S-EPMC9215701 | biostudies-literature

Ultraviolet photolysis of H2S and its implications for SH radical production in the interstellar medium.

Project description:Hydrogen sulfide radicals in the ground state, SH(X), and hydrogen disulfide molecules, H2S, are both detected in the interstellar medium, but the returned SH(X)/H2S abundance ratios imply a depletion of the former relative to that predicted by current models (which assume that photon absorption by H2S at energies below the ionization limit results in H + SH photoproducts). Here we report that translational spectroscopy measurements of the H atoms and S(1D) atoms formed by photolysis of jet-cooled H2S molecules at many wavelengths in the range 122 ≤ λ ≤155 nm offer a rationale for this apparent depletion; the quantum yield for forming SH(X) products, Γ, decreases from unity (at the longest excitation wavelengths) to zero at short wavelengths. Convoluting the wavelength dependences of Γ, the H2S parent absorption and the interstellar radiation field implies that only ~26% of photoexcitation events result in SH(X) products. The findings suggest a need to revise the relevant astrochemical models.

| S-EPMC7093389 | biostudies-literature

Infrared multiple photon dissociation of cesium iodide clusters doped with mono-, di- and triglycine.

Project description:Charged cesium iodide clusters doped with mono-, di- and triglycine serve as a model system for sea salt aerosols containing biological molecules. Here, we investigate reactions of these complexes under infrared irradiation, with spectra obtained by infrared multiple photon dissociation. The cluster ions are generated via electrospray ionization and analyzed in the cell of a Fourier Transform Ion Cyclotron Resonance Mass Spectrometer. Depending on the cluster size and peptide length, loss of HI or loss of a glycine unit is observed. The experimental measurements are supported by quantum chemical calculations. We show that N-H and O-H stretching modes dominate the spectrum, with large shifts depending on local interactions, namely due to interaction with iodide anions or intramolecular hydrogen bonding. Both experiment and theory indicate that several isomers are present in the experimental mixture, with different infrared fingerprints as well as dissociation pathways.

| S-EPMC7100558 | biostudies-literature

Origin of alkylphosphonic acids in the interstellar medium.

Project description:For decades, the source of phosphorus incorporated into Earth's first organisms has remained a fundamental, unsolved puzzle. Although contemporary biomolecules incorporate P(+V) in their phosphate moieties, the limited bioavailability of phosphates led to the proposal that more soluble P(+III) compounds served as the initial source of phosphorus. Here, we report via laboratory simulation experiments that the three simplest alkylphosphonic acids, soluble organic phosphorus P(+III) compounds, can be efficiently generated in interstellar, phosphine-doped ices through interaction with galactic cosmic rays. This discovery opens a previously overlooked avenue into the formation of key molecules of astrobiological significance and untangles basic mechanisms of a facile synthesis of phosphorus-containing organics in extraterrestrial ices, which can be incorporated into comets and asteroids before their delivery and detection on Earth such as in the Murchison meteorite.

| S-EPMC6685711 | biostudies-literature

Formation of benzene in the interstellar medium.

Project description:Polycyclic aromatic hydrocarbons and related species have been suggested to play a key role in the astrochemical evolution of the interstellar medium, but the formation mechanism of even their simplest building block--the aromatic benzene molecule--has remained elusive for decades. Here we demonstrate in crossed molecular beam experiments combined with electronic structure and statistical calculations that benzene (C(6)H(6)) can be synthesized via the barrierless, exoergic reaction of the ethynyl radical and 1,3-butadiene, C(2)H + H(2)CCHCHCH(2) ? C(6)H(6) + H, under single collision conditions. This reaction portrays the simplest representative of a reaction class in which aromatic molecules with a benzene core can be formed from acyclic precursors via barrierless reactions of ethynyl radicals with substituted 1,3-butadiene molecules. Unique gas-grain astrochemical models imply that this low-temperature route controls the synthesis of the very first aromatic ring from acyclic precursors in cold molecular clouds, such as in the Taurus Molecular Cloud. Rapid, subsequent barrierless reactions of benzene with ethynyl radicals can lead to naphthalene-like structures thus effectively propagating the ethynyl-radical mediated formation of aromatic molecules in the interstellar medium.

| S-EPMC3021054 | biostudies-other

Heavy N+ ion transfer in doubly charged N2Ar van der Waals cluster.

Project description:Van der Waals clusters are weakly bound atomic/molecular systems and are an important medium for understanding micro-environmental chemical phenomena in bio-systems. The presence of neighboring atoms may open channels otherwise forbidden in isolated atoms/molecules. In hydrogen-bond clusters, proton transfer plays a crucial role, which involves mass and charge migration over large distances within the cluster and results in its fragmentation. Here we report an exotic transfer channel involving a heavy N+ ion observed in a doubly charged cluster produced by 1?MeV Ne8+ ions: (N2Ar)2+?N++NAr+. The neighboring Ar atom decreases the [Formula: see text] barrier height and width, resulting in significant shorter lifetimes of the metastable molecular ion state [Formula: see text]([Formula: see text]). Consequently, the breakup of the covalent N+-N+ bond, the tunneling out of the N+ ion from the [Formula: see text] potential well, as well as the formation of an N-Ar+ bound system take place almost simultaneously, resulting in a Coulomb explosion of N+ and NAr+ ion pairs.

| S-EPMC7293282 | biostudies-literature

Infrared Multiple Photon Dissociation Spectroscopy of Cationized Canavanine: Side-Chain Substitution Influences Gas-Phase Zwitterion Formation†.

Project description:Infrared multiple photon dissociation spectroscopy was performed on protonated and cationized canavanine (Cav), a non-protein amino acid oxy-analog of arginine. Infrared spectra in the XH stretching region (3000 - 4000 cm-1) were obtained at the Centre Laser Infrarouge d'Orsay (CLIO) facility. Comparison of the experimental infrared spectra with scaled harmonic frequencies at the B3LYP/6-31+G(d,p) level of theory indicates that canavanine is in a canonical neutral form in CavH+, CavLi+, and CavNa+; therefore, these cations are charge-solvated structures. The infrared spectrum of CavK+ is consistent with a mixture of Cav in canonical and zwitterionic forms leading to both charge-solvated and salt-bridged cationic structures. The Cav moiety in CavCs+ is shown to be zwitterionic, forming a salt-bridged structure for the cation. Infrared spectra in the fingerprint region (1000 - 2000 cm-1) obtained at the FELIX Laboratory in Nijmegen, Netherlands support these assignments. These results show that that a single oxygen atom substitution in the side chain reduces the stability of the zwitterion compared to that of the protein amino acid arginine (Arg), which has been shown previously to adopt a zwitterionic structure in ArgNa+ and ArgK+. This difference can be explained in part due to the decreased basicity of Cav (PA = 1001 kJ/mol) as compared to arginine (PA = 1051 kJ/mol), but not entirely, as lysine, which has nearly the same proton affinity as Cav, (~993 kJ/mol) forms only canonical structures with Na+, K+, and Cs+. A major difference between the zwitterionic forms of ArgM+ and CavM+ is that the protonation site is on the side chain for Arg and on the N-terminus for Cav. This results in systematically weaker salt bridges in the Cav zwitterions. In addition, the presence of another hydrogen-bonding acceptor atom in the side chain contributes to the stability of the canonical structures for the smaller alkali cations.

| S-EPMC6020040 | biostudies-literature

Infrared multiple photon dissociation spectroscopy of a gas-phase oxo-molybdenum complex with 1,2-dithiolene ligands.

Project description:Electrospray ionization (ESI) in the negative ion mode was used to create anionic, gas-phase oxo-molybdenum complexes with dithiolene ligands. By varying ESI and ion transfer conditions, both doubly and singly charged forms of the complex, with identical formulas, could be observed. Collision-induced dissociation (CID) of the dianion generated exclusively the monoanion, while fragmentation of the monoanion involved decomposition of the dithiolene ligands. The intrinsic structure of the monoanion and the dianion were determined by using wavelength-selective infrared multiple-photon dissociation (IRMPD) spectroscopy and density functional theory calculations. The IRMPD spectrum for the dianion exhibits absorptions that can be assigned to (ligand) C ═ C, C-S, C-C ≡ N, and Mo ═ O stretches. Comparison of the IRMPD spectrum to spectra predicted for various possible conformations allows assignment of a pseudo square pyramidal structure with C2v symmetry, equatorial coordination of MoO(2+) by the S atoms of the dithiolene ligands, and a singlet spin state. A single absorption was observed for the oxidized complex. When the same scaling factor employed for the dianion is used for the oxidized version, theoretical spectra suggest that the absorption is the Mo ═ O stretch for a distorted square pyramidal structure and doublet spin state. A predicted change in conformation upon oxidation of the dianion is consistent with a proposed bonding scheme for the bent-metallocene dithiolene compounds [Lauher, J. W.; Hoffmann, R. J. Am. Chem. Soc. 1976 , 98 , 1729 - 1742], where a large folding of the dithiolene moiety along the S · · · S vector is dependent on the occupancy of the in-plane metal d-orbital.

| S-EPMC4338922 | biostudies-literature

Understanding and tuning blue-to-near-infrared photon cutting by the Tm3+/Yb3+ couple.

Project description:Lanthanide-based photon-cutting phosphors absorb high-energy photons and 'cut' them into multiple smaller excitation quanta. These quanta are subsequently emitted, resulting in photon-conversion efficiencies exceeding unity. The photon-cutting process relies on energy transfer between optically active lanthanide ions doped in the phosphor. However, it is not always easy to determine, let alone predict, which energy-transfer mechanisms are operative in a particular phosphor. This makes the identification and design of new promising photon-cutting phosphors difficult. Here we unravel the possibility of using the Tm3+/Yb3+ lanthanide couple for photon cutting. We compare the performance of this couple in four different host materials. Cooperative energy transfer from Tm3+ to Yb3+ would enable blue-to-near-infrared conversion with 200% efficiency. However, we identify phonon-assisted cross-relaxation as the dominant Tm3+-to-Yb3+ energy-transfer mechanism in YBO3, YAG, and Y2O3. In NaYF4, in contrast, the low maximum phonon energy renders phonon-assisted cross-relaxation impossible, making the desired cooperative mechanism the dominant energy-transfer pathway. Our work demonstrates that previous claims of high photon-cutting efficiencies obtained with the Tm3+/Yb3+ couple must be interpreted with care. Nevertheless, the Tm3+/Yb3+ couple is potentially promising, but the host material-more specifically, its maximum phonon energy-has a critical effect on the energy-transfer mechanisms and thereby on the photon-cutting performance.

| S-EPMC7305182 | biostudies-literature