Cococubed.com Iron Pseudocarbynes
Home Astronomy research   Software Infrastructure:      MESA      FLASH-X      STARLIB      MESA-Web      starkiller-astro      My instruments   Neutrino Emission:      De-excitation Neutrinos      Neutrino emission from stars      Identifying the Pre-SN      Neutrino HR diagram      Pre-SN Beta Processes      Pre-SN neutrinos   White dwarf pulsations:      12C(α,γ) & overshooting      Probe of 12C(α,γ)16O      Impact of 22Ne      Impact of ν cooling      Variable white dwarfs      MC reaction rates      Micronovae      Novae   White dwarf supernova:      Stable nickel production      Remnant metallicities      Colliding white dwarfs      Merging white dwarfs      Ignition conditions      Metallicity effects      Central density effects      Detonation density      Tracer particle burning      Subsonic burning fronts      Supersonic fronts      W7 profiles   Massive stars:      Pop III with HST/JWST      Rotating progenitors      3D evolution to collapse      MC reaction rates      Pre-SN variations   Massive star supernova:      Yields of radionuclides      26Al & 60Fe      44Ti, 60Co & 56Ni      SN 1987A light curve      Constraints on Ni/Fe      An r-process      Effects of 12C +12C   Neutron Stars and Black Holes:      Black Hole spectrum      Mass Gap with LVK      Compact object IMF      He burn neutron stars   Stars:      Hypatia catalog      SAGB stars      Nugrid Yields I      He shell convection      BBFH at 40 years      γ-rays within 100 Mpc      Iron Pseudocarbynes   Pre-Solar Grains:      C-rich presolar grains      SiC Type U/C grains      Grains from massive stars      Placing the Sun      SiC Presolar grains   Chemical Evolution:      Radionuclides in 2020s      Zone models H to Zn      Mixing ejecta   Thermodynamics, Opacities & Networks      Radiative Opacity      Skye EOS      Helm EOS      Five EOSs      Equations of State      12C(α,γ)16O Rate      Proton-rich NSE      Reaction networks      Bayesian reaction rates   Verification Problems:      Validating an astro code      Su-Olson      Cog8      Mader      RMTV      Sedov      Noh Software Instruments AAS Journals    2025 AAS YouTube    2025 AAS Peer Review Workshops 2025 ASU Energy in Everyday Life 2025 MESA Classroom Other Stuff:    Bicycle Adventures    Illustrations    Presentations Contact: F.X.Timmes my one page vitae, full vitae, research statement, and teaching statement.	On the Structure, Magnetic Properties, and Infrared Spectra of Iron Pseudocarbynes in the Interstellar Medium (2019) Carbon chains, especially polyynes, are the building blocks of complex molecules such as polycyclic aromatic hydrocarbons and fullerenes, and polyynes are observed in circumstellar and interstellar (CIS) environments. Yet these same CIS environments show only low levels of gaseous iron despite it being the fourth most abundant element in the solar abundance pattern. In this article we explore the structure, magnetic properties, and synthetic infrared (IR) spectra of iron bound to polyynes, yielding what we call iron pseudocarbynes. We find that polyynes of all lengths are characterized by an IR-active CH stretching feature at λ ∼ 3 μm, and an IR-active CCH/CCC bending feature at $\lambda \simeq$ 16 μm. The CCH bending feature exhibits a redshift in iron pseudocarbynes such as Fe12C2H2, appearing at $\lambda \simeq$ 15.8 μm with an IR intensity that is reduced by a factor of ∼ 5. Similarly, iron pseudocarbynes with different carbon-chain lengths such as Fe13C2H2 and Fe13(C2H2)6 also show IR features at nearly the same wavelengths with reduced IR intensities. Iron pseudocarbynes may have been overlooked because, based on calculations, their IR spectra are, within experimental uncertainties, identical to astronomically observed, iron-free species. The occurrence of iron pseudocarbynes in CIS environments would enhance Fe depletion, facilitate production of thermodynamically stable long-chain polyynes, provide a catalytic bridge over the composition gap between molecules containing nine or fewer carbon atoms and complex molecules, and supply a potential mechanism for the modulation and polarization of magnetic fields in CIS environments. IR spectra of C9NH and different CnH2 IR spectra of Fe13-C6H2 and Fe13-(C6H2)6 Spin densities of Fe13-(C6H2)6