Interaction Of Low-energy Electrons Research Articles

Low-energy electron interactions with chlorotrimethylsilane (Si(CH3 )3 Cl), dichlorodimethylsilane (Si(CH3 )2 Cl2 ) and chloromethyldimethylsilane (SiH(CH3 )2 (CH2 Cl)).

Silane derivatives are widely used in industrial plasmas for manufacturing lighting devices, solar cells, displays, etc. Models of technological plasmas require quantitative data. The rate coefficients (k) and the activation energies (Ea ) of thermal electron attachment for chlorotrimethylsilane (Si(CH3 )3 Cl), dichlorodimethylsilane (Si(CH3 )2 Cl2 ) and chloromethyldimethylsilane (SiH(CH3 )2 (CH2 Cl)) are reported. This is important for understanding the basic processes occurring in plasmas. The pulsed Townsend technique (known as the electron swarm method) has been applied for the measurements. In this technique, electrons generated by a laser, under a uniform electric field, traverse to an anode and induce a charge on it. In the buffer gas charge grows linearly, but in the presence of a scavenger, electrons are captured, and thus the rate of charge increase slows down with time. From the shape of the pulse, the kinetic parameters are determined. Kinetic parameters from the study of thermal electron attachment by Si(CH3 )3 Cl, Si(CH3 )2 Cl2 and SiH(CH3 )2 (CH2 Cl) were determined for the first time. The corresponding rate coefficients at 298 K are equal to (9.56 ± 0.02) × 10-11 , (6.62 ± 0.02) × 10-11 and (1.24 ± 0.05) × 10-11 cm3 s-1 and Ea values are equal to 0.29 ± 0.01, 0.24 ± 0.01 and 0.31 ± 0.01eV for Si(CH3 )3 Cl, Si(CH3 )2 Cl2 and SiH(CH3 )2 (CH2 Cl), respectively. The experiment was performed in the 298-378K temperature range. The presented results provide important new information about fundamental quantities such as rate coefficients and activation energies for thermal electron capture by chlorinated derivatives of silane. These data can further advance our understanding of thermal electron interactions with chlorosilanes that can be used to control the important species in the plasmas of many modern technologies.

Fragmentation of Nickel(II) and Cobalt(II) Bis(acetylacetonate) Complexes Induced by Slow (

Metal acetylacetonate complexes have high potentiality in nanoscale fabrication processes (e.g., focus electron beam-induced deposition) thanks to the versatile character and ease of preparation compounds. In this work, we study and compare the physics and the physicochemistry induced by the interaction of low-energy (<10 eV) electrons with nickel(II) and cobalt(II) bis(acetylacetonate) complexes. The slow particles decompose the molecules via dissociative electron attachment. The nickel(II) and cobalt(II) bis(acetylacetonate) anions and the acetylacetonate negative fragments are the most dominant detected species. The experimental data are completed with density functional theory calculations to provide information on the electronic states of the molecules and the energetics for fragmentation. Finally, it is found that the interaction of low-energy electrons resulting in the decomposition of organometallic complexes in the gas phase is more efficient with the nickel(II) than with the cobalt(II) bis(acetylacetonate) complex. These results are found to be in a relative agreement with the surface experiments.

DFT study of low-energy electron interaction with pyridine, pyrazine and their halo derivatives

In this work, the density functional theory with B3LYP hybrid functional was employed to calculate quantities useful for estimating the behavior of pyridine, pyrazine and their derivatives monosubstituted with Cl or Br atom, when exposed to low-energy electron impact. Vertical electron affinities obtained in several Pople basis sets and in aug-cc-pVTZ basis set are reported. Although some of the investigated molecules do not form stable anions, the results are in a satisfactory agreement with the available, albeit sparse experimental data, if the diffuse functions are included in calculations. It was found that the 6-31+G* basis is sufficient and its further enlargement does not significantly change the results. At this level of theory, potential energy curves, supported by enthalpies of dissociation to the neutral and anion fragment, were also determined for the description of the dissociative electron attachment. According to B3LYP, the potential energy curves of the halogen bond are almost repulsive in halopyridines, whereas halopyrazine anions require small activation energy for dissociation. Vertical electron affinities, enthalpies and equilibrium C-X distances (X=H, Cl, Br) were also calculated using Møller-Plesset second-order perturbation theory.Graphic

Low-energy electron inelastic mean free path and elastic mean free path of graphene

Based on a recent experimental data of elastic transmissivity and the elastic reflectivity measured on graphene, we have performed a theoretical study on electron inelastic mean free path (IMFP) and elastic mean free path (EMFP) by an improved approximation in a classical electron trajectory framework. A hump feature, which is considered to be owing to the out-of-plane mode of the π + σ plasmon, is clearly shown in our IMFP results of multilayer graphene while it is not seen in that of monolayer graphene. The obtained EMFPs are one order of magnitude greater than previously reported results. This work shows that the classical electron trajectory framework still works for revealing the physics picture of low-energy electron interaction with graphene, even for the transverse direction of monolayer graphene, which is the thinnest material.

Взаимодействие низкоэнергетических электронов с молекулами D-рибозы

Abstract– The interactions of low-energy electrons (&lt;20 eV) with D-ribose molecules, namely, electron scattering and dissociative attachment, are studied. The results of these studies showed that the fragmentation of D-ribose molecules occurs effectively even at an electron energy close to zero. as well as in the energy range 5.50–9.50 eV. In the total cross section of electron scattering by molecules, resonance features at energies of 5.00–9.00 eV in the region of formation of ionic fragments C3H4O2–, C2H3O2–, OH–, associated with the destruction of molecular heterocycles, were experimentally discovered for the first time. The correlation of the features observed in the scattering and dissociative electron attachment cross sections is analyzed.

5-Nitro-2,4-Dichloropyrimidine as an Universal Model for Low-Energy Electron Processes Relevant for Radiosensitization.

We report experimental results of low-energy electron interactions with 5-nitro-2,4-dichloropyrimidine isolated in the gas phase and hydrated in a cluster environment. The molecule exhibits a very rare combination of many so far hypothesized low-energy electron induced mechanisms, which may be responsible for synergism in concurrent chemo-radiation therapy of cancer. In contrast to many previous efforts to design an ideal radiosensitizer based on one mode of action, the present model molecule presents an alternative approach, where several modes of action are combined. With respect to the processes induced by the low-energy electrons, this is not a trivial task because of strong bond specificity of the dissociative electron attachment reaction, as it is discussed in the present paper. Unfortunately, low solubility and high toxicity of the molecule, as obtained from preliminary MTT assay tests, do not enable further studies of its activity in real biological systems but it can advantageously serve as a model or a base for rational design of radiosensitizers.

SARS-CoV-2 Rapid Detection System using Electric Current-Spectrum for Human Exhaled Air Samples

The SARS-COV-2 Rapid Detection System is a SARS-COV-2 Electro-Spectroscopy detection system. The preliminary design of this system was studied theoretically in this paper. This system can detect the existence of sub-micro impurity particles in the human exhaled air, based on the unique shape, dimensions and density of these sub-micro impurities, such as viral particles, including CORONA viruses. This information is carried out by electron current buildup forming Electric Current-Spectrum (ECS) distinguishing the contents of the exhaled air. The design is based on Flashing Ratchet Potential (FRP) and beam of free electrons passing through the electrodes of the FRP. The ECS is characterized by curve deviations caused by interaction of low energy electrons’ (-β radiation) with matter, which depends on the matter’s shape, dimension and density. This interaction causes a scattering (delaying) or absorption of the electrons by matter, by elastic or inelastic collisions, respectively. The ability of FRP to drift back the delayed electrons to their initial points can be used to characterize the produced ECS. The effect of delayed electrons can be amplified to form a visualized deviation in the ECS by electron multiplication system and can be interpreted into distinguishable SARS-COV-2 Barcodes or Fingerprints.

Ionizing radiation and natural constituents of living cells: Low-energy electron interaction with coenzyme Q analogs.

Resonance electron attachment to short-tail analogs of coenzyme Q10 is investigated in the electron energy range 0 eV-14 eV under gas-phase conditions by means of dissociative electron attachment spectroscopy. Formation of long-lived (milliseconds) molecular negative ions is detected at 1.2 eV, but not at thermal energy. A huge increase in the electron detachment time as compared with the reference para-benzoquinone (40 µs) is ascribed to the presence of the isoprene side chains. Elimination of a neutral CH3 radical is found to be the most intense decay detected on the microsecond time scale. The results give some insight into the timescale of electron-driven processes stimulated in living tissues by high-energy radiation and are of importance in prospective fields of radiobiology and medicine.

Low energy electron interactions with Iodine molecule (I2)

A theoretical analysis is performed for electron interactions with the Iodine molecule (I2) for incident energies ranging from 0.1 eV to 20 eV. The calculations were carried out using Quantemol-N package, which uses the UK Molecular R-matrix Codes. Electron interactions with the I2 molecule have been studied with several target models in its equilibrium geometry, and the results are reported for the optimized target model. Scattering calculations are performed to provide resonance parameters along with Dissociative Electron Attachment (DEA) Cross-Sections. In addition, the study also focussed on the estimation of various cross-sections such as elastic, electronic excitation, differential, momentum transfer, ionization and total cross-sections. Many of these cross-sections reported here are for the first time for electron interaction with the iodine molecule to the best of our knowledge.

Interaction of Slow Electrons with Thermally Evaporated Manganese(II) Acetylacetonate Complexes.

Complexes of metal acetylacetonate are used as general precursors for the synthesis of metal oxide nanomaterials. In the present work, we study the interaction of low-energy (<10 eV) electrons, produced abundantly as secondary electrons during the bombardment of the substrate by the primary particles, with thermally evaporated manganese(II) acetylacetonate complexes. We found that the acetylacetonate anion ([acac]-) is the major anionic species produced, while the second most abundant is the parent anion [Mn(II)(acac)2]-. This observation differs from those reported from electron attachment to Cu(acac)2, for which [Cu(II)(acac)2]- is the predominant anion [Kopyra et al. Phys. Chem. Chem. Phys. 2018, 20, 7746]. The experimental data are supported by theory to provide information on the physical-chemistry processes initiated by slow electrons to the organometallic precursor and to interpret the different behavior of Mn(acac)2 compared to Cu(acac)2.

Direct Damage of Deoxyadenosine Monophosphate by Low Energy Electrons Probed by X-Ray Photoelectron Spectroscopy

Low-energy (3-25 eV) electron interactions with multilayers of 2'-deoxyadenosine 5'-monophosphate (dAMP) were probed using X-ray photoelectron spectroscopy (XPS). Understanding how electrons damage the nucleotide dAMP, which is a building block of DNA, can give insight into how the DNA undergoes radiation damage. Chemical modifications to the constituent units of the nucleotide were revealed in situ through monitoring of the O 1s, C 1s, and N 1s elemental transitions. It is shown that direct electron irradiation causes decomposition of both the base and sugar subunits, as well as cleavage of glycosidic and phosphoester bonds. Incident electrons undergo inelastic energy losses, including creation of core-excited resonances above 3-4 eV. In the condensed phase, these resonances decay via autoionization, producing electronically excited targets and <3 eV electrons. The excited states dissociate and the slow (<3 eV) electrons are captured by neighboring molecules, forming molecular shape resonances that can lead to bond rupture. Since the observed chemical changes were similar at all incident electron energies studied, they can be primarily attributed to formation and decay of transient negative ions. Damage enhancements in the energy ranges typical of all scattering resonances are expected, with the damage probability dominated by the low-energy shape resonances.

Structural rearrangements as relaxation pathway for molecular negative ions formed via vibrational Feshbach resonance.

The low-energy (0-15 eV) resonance electron interaction with two organic acids, oxaloacetic and α-ketoglutaric, is studied under gas-phase conditions using dissociative electron attachment spectroscopy. The most unexpected observation is the long-lived (microseconds) molecular negative ions formed by thermal electron attachment via the vibrational Feshbach resonance mechanism in both compounds. Unlike oxaloacetic acid, for which only one slow (microseconds) dissociative decay is detected, as many as five metastable negative ions are observed for α-ketoglutaric acid. These results are analyzed using density functional theory calculations and estimations of electron affinity using the experimental electron detachment times. The results are of considerable interest for understanding the fundamental mechanisms responsible for the dynamics of highly excited negative ions and the transformation pathways of biologically relevant molecules stimulated by excess electron attachment.

A comparative study on Monte Carlo simulations of electron emission from liquid water.

Liquid water being the major constituent of the human body, is of fundamental importance in radiobiological research. Hence, the knowledge of electron-water interaction physics and particularly the secondary electron yield is essential. However, to date, only very little is known experimentally on the low energy electron interaction with liquid water because of certain practical limitations. The purpose of this study was to gain some useful information about electron emission from water using a Monte Carlo (MC) simulation technique that can numerically model electron transport trajectories in water. In this study, we have performed MC simulations of electron emission from liquid water in the primary energy range of 50eV-30keV by using two different codes, i.e., a classical trajectory MC (CMC) code developed in our laboratory and the Geant4-DNA (G4DNA) code. The calculated secondary electron yield and electron backscattering coefficient are compared with experimental results wherever applicable to verify the validity of physical models for the electron-water interaction. The secondary electron yield vs. primary energy curves calculated using the two codes present the same generic curve shape as that of metals but in rather different absolute values. G4DNA underestimates the secondary electron yield due to the application of one step thermalization model by setting a cutoff energy at 10eV so that the low energy losses due to phonon excitations are omitted. Our CMC code, using a full energy loss spectrum to model electron inelastic scattering, allows the simulation of individual phonon scattering events for very low energy losses down to 10 meV, which then enables the calculated secondary electron yields much closer to the experimental data and also gives quite reasonable energy distribution curve of secondary electrons. It is concluded that full dielectric function data at low energy loss values below 10eV are recommended for modeling of low energy electrons in liquid water.

Secondary electron generation mechanisms in carbon allotropes at low impact electron energies

More than a century after the discovery of the electron, there are still fundamental, yet unresolved, questions concerning the generation-ejection mechanism of the ubiquitous Secondary Electrons (SEs) from a solid surface. Broadness of the field of application for these SEs makes it desirable to be able to control this phenomenon, which requires the understanding of the elementary physical mechanism leading to their generation and emission. This paper reports on the dissection of such a tangled process operated by the help of spectroscopic tools of increasing finesse; measuring differential cross sections with an increasing degree of differentiation. These results demonstrate that single ionising scattering events, assisted by collective excitations, constitute the fundamental ingredient leading to SE-generation and -emission. To this end, the interaction of Low Energy Electrons (LEEs) with various Carbon allotropes has been investigated by means of Total Electron Yield (TEY) and (e,2e)-coincidence spectroscopy measurements. Carbon allotropes are chosen as targets since they are important in technological applications where both minimisation and maximisation of the SE-yield is a relevant issue. This is the first time that such complete set of benchmarks on the SE-yield from well characterised surfaces has been gathered, interpreted and is made available to the scientific community. This comprehensive investigation has led to the disentanglement of the elementary processes relevant for the understanding of the SE-generation probability, that fully take into account both energy and momentum conservation in the collision and the band structure of the solid as well as many-body effects.

Low energy electron interactions with 1-decanethiol self-assembled monolayers on Au(111)

Understanding the interaction of low energy electrons with organic thin films is important for the development of a wide range of technological applications. In this study, the interaction of 80 eV electrons with self-assembled monolayers (SAMs) of 1-decanethiol grown on Au(111) via vapor phase deposition was explored for both the lying down (striped) phase and the standing up phase. Low-energy electron diffraction measurements performed at 100 K show that the SAM loses its crystalline structure within about 3 min for the lying down phase and approximately 30 s for the standing up phase. For the standing up phase, temperature programed desorption measurements reveal two desorption features for the hydrocarbon fragments of the SAM, one centered around 130 °C and a second near 220 °C. For the lying down phase, only the higher temperature desorption feature is observed. For both phases, desorption peaks for S and H2S that are centered around 250 °C were observed, suggesting that there is a high probability for the alkane chain of the 1-decanethiol molecule to detach from the sulfur head group before desorbing from the surface. For the standing up phase, exposing the SAM to the electron beam results in a near complete attenuation of the two peaks associated with the cracking fragments of the alkane chain. However, for the lying down phase, the intensities and positions of all of the desorption peaks were similar to the unexposed SAMs, which indicates that the cross section for electron beam damage for the lying down phase is much lower than that for the standing up phase. Ex situ x-ray photoelectron spectroscopy reveals a chemical shift of almost 0.5 eV for the C-1s emission after electron exposure for the standing up phase, whereas the shift for the lying down phase was less than 0.1 eV. These results indicate that exposure of alkanethiol SAMs to 80 eV electrons results in both disordering of the SAM and decomposition of the alkanethiol molecule SAMs. For the standing up phase, the rate of decomposition is much higher than the lying down phase. The lower decomposition rate for the lying down phase is primarily attributed to the quenching of excess charge in this phase since the entire molecule is in direct contact with the metallic substrate.

Interaction of low-energy electrons with surface polarity near ferroelastic domain boundaries

We derive surface polarity at and near ferroelastic domain boundaries from molecular dynamics simulations based on an ionic spring model. Interatomic gradient forces lead to flexoelectricity which, in turn, generates polarity at the surface and in twin boundaries. We then derive generic properties of electron scattering spectra equivalent to those observed in low-energy electron microscopy (LEEM) and mirror electron microscopy (MEM) experiments. Negatively (positively) charged surfaces reflect (attract) incident electrons with low kinetic energy. The electron images reveal the valley and ridge surface structures near the intersection of the twin boundary and the surface. Polarity in surface layers is predicted to be visible in LEEM and MEM spectra at neutral surfaces, but much less when surfaces are charged. Inward polarity reflects electrons similar to negative surface charges, and outward polarity backscatters electrons like positive surface charges. Both the polarity in the twin boundary and the physical topography scatter electrons, consistent with experimental LEEM and MEM experiments on CaTiO3 with (001) and (111) surface terminations.

Low-energy electron dose-point kernels and radial dose distributions around gold nanoparticles: Comparison between MCNP6.1, PENELOPE2014 and Geant4-DNA

Abstract With emerging interests in subcellular and nano-scale energy deposition of low-energy electrons, new cross-sectional models for the low-energy electron transport have been integrated into recent releases of Monte Carlo (MC) codes. MCNP6.1 has been released which included extended cross-sections for low-energy electron interactions based on the Evaluated Electron Data Library (EEDL). Moreover, a single-event electron transport method was introduced down to 10 eV. In this study, MCNP6.1 has been benchmarked against early versions of PENELOPE2014 and Geant4-DNA by comparing dose-point kernels (DPKs) of electrons of 100 eV, 1 keV and 10 keV. In addition, radial dose distributions around a 2 or 15 nm-diameter gold nanoparticle (GNP) irradiated by 50 kVp X-rays were calculated for comparison. For all electron energies, the DPKs calculated by MCNP6.1 reached the maximum values at shorter distances and then were decreased more rapidly than those calculated by the other codes. Radial doses within 2 nm from the surface of the GNPs calculated by MCNP6.1 were 1.04 – 1.89 times and 1.13 – 1.58 times higher than those calculated by Geant4-DNA and PENELOPE2014, respectively. These differences would stem from the fact that inelastic cross-sections of MCNP6.1 for low-energy electrons are higher than those of the other codes. At this moment, it is difficult to judge which of the codes is more accurate for nano-scale dose calculations than the others. Depending on the geometrical configuration of the electron source (herein GNPs) and the target (e.g., DNA), the difference in the interaction data for low-energy electron transport, especially below 10 keV, would result in significant differences in calculation of radio-biological effects on the target. It can be concluded that one should pay attention to the interaction data as well as the transport parameters used for MC low-energy radiation transport in a nano- and micro-scale.

Effective and absolute cross sections for low-energy (1-30 eV) electron interactions with condensed biomolecules

Ionizing radiation is intensively used for therapeutic [e.g., radiotherapy, brachytherapy, and targeted radionuclide therapy (TRT)], as well as for diagnostic medical imaging purposes. In these applications, the radiation dose given to the patient should be known and controlled. In conventional cancer treatments, absorbed dose calculations rely essentially on scattering cross sections (CSs) of the primary high-energy radiation. In more sophisticated treatments, such as combined radio- and chemo-therapy, a description of the details of energy deposits at the micro- and nano-scopic level is preferred to relate dose to radiobiological effectiveness or to evaluate doses at the biomolecular level, when radiopharmaceuticals emitting short-range radiation are delivered to critical molecular components of cancer cells (e.g., TRT). These highly radiotoxic compounds emit large densities of low-energy electrons (LEEs). More generally, LEE (0-30 eV) are emitted in large numbers by any type of high-energy radiation; i.e., about 30 000 per MeV of deposited primary energy. Thus, to optimize the effectiveness of several types of radiation treatments, the energy deposited by LEEs must be known at the level of the cell, nucleus, chromosome, or DNA. Such local doses can be evaluated by Monte Carlo (MC) calculations, which account event-by-event, for the slowing down of all generations of particles. In particular, these codes require as input parameters absolute LEE CSs for elastic scattering, energy losses, and direct damage to vital cellular molecules, particularly DNA, the main target of radiation therapy. In the last decade, such CSs have emerged in the literature. Furthermore, a method was developed to transform relative yields of damages into absolute CSs by measuring specific parameters in the experiments. In this review article, we first present a general description of dose calculations in biological media via MC simulation and give an overview of the CSs available from theoretical calculations and gas-phase experiments. The properties of LEE scattering in the gas-phase are then compared to those in the condensed phase. The remaining portion of the article is devoted to condensed-phase CSs. We provide absolute LEE scattering CSs for electronic, vibrational, and phonon excitation of biomolecules as well as for dissociative electron attachment, electron intra- and inter-molecular stabilization, and bond dissociation, including strand breaks and degradation product formation. The biomolecules are O2, CO2, H2O, DNA bases, sugar and phosphate unit analogs, oligonucleotides, plasmid DNA, and the amino acid tryptophan. CSs for strand breaks in radiosensitizing and chemotherapeutic molecules bond or not to a short DNA strand are also listed. The principle of each experimental technique and mathematical methods utilized to generate all condensed-phase CSs are briefly explained. The mechanisms responsible for the magnitudes of the CSs are discussed.

Electronic Resonances of Nucleobases Using Stabilization Methods.

The interaction of low-energy electrons with nucleobases is important because of their potential to damage nucleic acids. In this work we investigate several low-lying resonances of nucleobases using quantum chemical methods including static and dynamical correlation coupled with orbital stabilization methods. Specifically, the equation of motion for electron affinities via couple cluster singles and doubles and multireference perturbation theory methods were used, and their performance was explored. Low-lying π* resonances were calculated and compared to previous theoretical and experimental results, showing good agreement for positions and widths. Feshbach/Core-excited resonances generated by attachment of an electron to a ππ* excited state of the bases were also calculated, providing for the first time accurate information for these resonances. Mixing between configurations corresponding to shape and Feshbach/core-excited resonances is present in all nucleobases, which complicates the theoretical treatment and necessitates multiconfigurational approaches for a proper description.

Electron interactions with the heteronuclear carbonyl precursor H2FeRu3(CO)13 and comparison with HFeCo3(CO)12: from fundamental gas phase and surface science studies to focused electron beam induced deposition.

In the current contribution we present a comprehensive study on the heteronuclear carbonyl complex H2FeRu3(CO)13 covering its low energy electron induced fragmentation in the gas phase through dissociative electron attachment (DEA) and dissociative ionization (DI), its decomposition when adsorbed on a surface under controlled ultrahigh vacuum (UHV) conditions and exposed to irradiation with 500 eV electrons, and its performance in focused electron beam induced deposition (FEBID) at room temperature under HV conditions. The performance of this precursor in FEBID is poor, resulting in maximum metal content of 26 atom % under optimized conditions. Furthermore, the Ru/Fe ratio in the FEBID deposit (≈3.5) is higher than the 3:1 ratio predicted. This is somewhat surprising as in recent FEBID studies on a structurally similar bimetallic precursor, HFeCo3(CO)12, metal contents of about 80 atom % is achievable on a routine basis and the deposits are found to maintain the initial Co/Fe ratio. Low temperature (≈213 K) surface science studies on thin films of H2FeRu3(CO)13 demonstrate that electron stimulated decomposition leads to significant CO desorption (average of 8–9 CO groups per molecule) to form partially decarbonylated intermediates. However, once formed these intermediates are largely unaffected by either further electron irradiation or annealing to room temperature, with a predicted metal content similar to what is observed in FEBID. Furthermore, gas phase experiments indicate formation of Fe(CO)4 from H2FeRu3(CO)13 upon low energy electron interaction. This fragment could desorb at room temperature under high vacuum conditions, which may explain the slight increase in the Ru/Fe ratio of deposits in FEBID. With the combination of gas phase experiments, surface science studies and actual FEBID experiments, we can offer new insights into the low energy electron induced decomposition of this precursor and how this is reflected in the relatively poor performance of H2FeRu3(CO)13 as compared to the structurally similar HFeCo3(CO)12.