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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Ir(SeBr3)3 by Materials Project

IrSe3Br8Br crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four hydrobromic acid molecules and four IrSe3Br8 clusters. In each IrSe3Br8 cluster, Ir3+ is bonded in a T-shaped geometry to three Se2- atoms. There are a spread of Ir–Se bond distances ranging from 2.37–2.49 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to one Ir3+ and four Br+0.33+ atoms. There are a spread of Se–Br bond distances ranging from 2.39–3.03 Å. In the second Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to one Ir3+ and two Br+0.33+ atoms. There are one shorter (2.36 Å) and one longer (2.42 Å) Se–Br bond lengths. In the third Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to one Ir3+ and two Br+0.33+ atoms. There are one shorter (2.36 Å) and one longer (2.38 Å) Se–Br bond lengths. There are eight inequivalent Br+0.33+ sites. In the first Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the second Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the third Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the fourth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the fifth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the sixth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the seventh Br+0.33+ site, Br+0.33+ is bonded in a distorted single-bond geometry to one Se2- atom. In the eighth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ir(N2Cl3)2 by Materials Project

IrCl6(N2)2 is Fluorite structured and crystallizes in the tetragonal I4mm space group. The structure is zero-dimensional and consists of four nitrogen molecules and two IrCl6 clusters. In each IrCl6 cluster, Ir4+ is bonded in an octahedral geometry to six Cl1- atoms. There are one shorter (2.27 Å) and five longer (2.31 Å) Ir–Cl bond lengths. There are three inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a single-bond geometry to one Ir4+ atom. In the second Cl1- site, Cl1- is bonded in a single-bond geometry to one Ir4+ atom. In the third Cl1- site, Cl1- is bonded in a single-bond geometry to one Ir4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ir(SeBr3)3 by Materials Project

IrSe3Br7(Br)2 crystallizes in the triclinic P-1 space group. The structure is zero-dimensional and consists of four hydrobromic acid molecules and two IrSe3Br7 clusters. In each IrSe3Br7 cluster, Ir3+ is bonded in a distorted T-shaped geometry to three Se2- atoms. There are a spread of Ir–Se bond distances ranging from 2.40–2.44 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to one Ir3+ and two Br+0.33+ atoms. There are one shorter (2.38 Å) and one longer (2.40 Å) Se–Br bond lengths. In the second Se2- site, Se2- is bonded in a trigonal non-coplanar geometry to one Ir3+ and two Br+0.33+ atoms. There are one shorter (2.38 Å) and one longer (2.42 Å) Se–Br bond lengths. In the third Se2- site, Se2- is bonded in a distorted trigonal non-coplanar geometry to one Ir3+ and three Br+0.33+ atoms. There are a spread of Se–Br bond distances ranging from 2.39–3.00 Å. There are seven inequivalent Br+0.33+ sites. In the first Br+0.33+ site, Br+0.33+ is bonded in a distorted single-bond geometry to one Se2- atom. In the second Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the third Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the fourth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the fifth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the sixth Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom. In the seventh Br+0.33+ site, Br+0.33+ is bonded in a single-bond geometry to one Se2- atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ir(Br3O)2 by Materials Project

IrBr6O2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is zero-dimensional and consists of eight water molecules and four IrBr6 clusters. In each IrBr6 cluster, Ir4+ is bonded in an octahedral geometry to six equivalent Br atoms. All Ir–Br bond lengths are 2.43 Å. Br is bonded in a single-bond geometry to one Ir4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ir(Br3N)2 by Materials Project

IrBr6N2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is zero-dimensional and consists of eight ammonia molecules and four IrBr6 clusters. In each IrBr6 cluster, Ir4+ is bonded in an octahedral geometry to six equivalent Br1- atoms. All Ir–Br bond lengths are 2.46 Å. Br1- is bonded in a single-bond geometry to one Ir4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ir(NCl3)2 by Materials Project

IrCl6N2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is zero-dimensional and consists of eight ammonia molecules and four IrCl6 clusters. In each IrCl6 cluster, Ir4+ is bonded in an octahedral geometry to six equivalent Cl1- atoms. All Ir–Cl bond lengths are 2.30 Å. Cl1- is bonded in a single-bond geometry to one Ir4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2024

In situ X-ray and IR probes relevant to Earth science at the Advanced Light Source at Lawrence Berkeley Laboratory

Access to synchrotron X-ray facilities has become an important aspect for many disciplines in experimental Earth science. This is especially important for studies that rely on probing samples in situ under natural conditions different from the ones found at the surface of the Earth. The non-ambient condition Earth science program at the Advanced Light Source (ALS), Lawrence Berkeley National Laboratory, offers a variety of tools utilizing the infra-red and hard X-ray spectrum that allow Earth scientists to probe Earth and environmental materials at variable conditions of pressure, stress, temperature, atmospheric composition, and humidity. These facilities are important tools for the user community in that they offer not only considerable capacity (non-ambient condition diffraction) but also complementary (IR spectroscopy, microtomography), and in some cases unique (Laue microdiffraction) instruments. The availability of the ALS’ in situ probes to the Earth science community grows especially critical during the ongoing dark time of the Advanced Photon Source in Chicago, which massively reduces available in situ synchrotron user time in North America.

58 GEOSCIENCES↗
DOE OSTI2021

Ir-192 radioisotope replacement with a hand-portable 1 MeV Ku-band electron linear accelerator

Although linear accelerators are used in many security, industrial and medical applications, the existing technologies are too large and expensive for several critical applications such as radioactive source replacement, field radiography and mobile cargo scanners. Here, one of the main requirements for these sources is to be highly portable to allow field operation. In response to this problem, RadiaBeam has designed a hand-portable 1 MeV X-ray source, scalable to higher energies, based on Ku-band split electron linac, that can be used for Ir-192 radioisotope replacement. In this paper, we present its multiphysics and engineering design studies, as well as an accelerating structure prototype along with RF measurements.

43 PARTICLE ACCELERATORS↗
DOE OSTI2022

Heteroatom substitution for the development of near-IR lumiphores

Near-IR (NIR) lumiphores are advantageous for biological applications as their emission falls within the tissue-transparent region. Furthermore, these dyes suffer from low quantum yields as a consequence of their low transition energy. Heteroatom substitution has recently been successfully used to bathochromically shift emission in various dye scaffolds while maintaining bright emission.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Acceleration of Near-IR Emission through Efficient Surface Passivation in Cd 3 P 2 Quantum Dots

Fast near-IR (NIR) emitters are highly valuable in telecommunications and biological imaging. The most established NIR emitters are epitaxially grown In x Ga 1-x As quantum dots (QDs), but epitaxial growth has several disadvantages. Colloidal synthesis is a viable alternative that produces a few NIR-emitting materials, but they suffer from long photoluminescence (PL) times. These long PL times are intrinsic in some NIR materials (PbS, PbSe) but are attributed to emission from bright trapped carrier states in others. We show that Cd 3 P 2 QDs possess substantial trap emission with radiative times >10 1 ns. Surface passivation through shell growth or coordination of Lewis acids is shown to accelerate the NIR emission from Cd 3 P 2 QDs by decreasing the amount of trap emission. This finding brings us one step closer to the application of colloidally synthesized QDs as quantum emitters.

36 MATERIALS SCIENCE↗
NASA NTRS2003

Mid-IR semiconductor lasers for chemical sensing

The development of mid-IR semiconductor diode lasers based on type-II interband cascade structures is presented. How these diode lasers can be developed to meet the requirements in chemical sensing applications is discussed.

interband cascade lasers chemical sensing mid-IR↗
NASA NTRS2014

SOFIA FORCAST Far-IR Photometry of Comet ISON and Constraints on the Coma Grain Size Distribution

Comet C/2012 S1 (ISON) was unique in that it was a dynamically new comet derived from the nearly isotropic Oort cloud reservoir of comets with a sun-grazing orbit. Infrared (IR) observations were executed on NASA's Stratospheric Observatory For Infrared Astronomy (SOFIA) by the FORCAST instrument on 2013 October 25 UT (r(sub h)=1.18 AU, Delta=1.5AU). Photometry was obtained in FORCAST filters centered at 11.1, 19.7, and 31.5 micron. The observations compliment a large world-wide effort to observe and characterize comet ISON.

Comet dust properties↗
NASA NTRS2011

Ultra-Sensitive Transition-Edge Sensors (TESs) for Far-IR/Submm Space-Borne Spectroscopy

We have built surface micromachined thin-film metallized Si(x)N(y) optical absorbers for transition-edge sensors (TESs) suitable for the Background - Limited far-IR/Submm Spectrograph (BLISS). BLISS is a broadband (38 micrometers - 433 micrometers), grating spectrometer consisting of five wavebands each with a modest resolution of R (is) approx. 1000. Because BLISS requires the effective noise equivalent power (NEP) of the TES to be below 10 (exp 19) W/Hz(exp 1/2), our TESs consist of four long (1000 micrometers), narrow (0.4 micrometers ), and thin (0.25 micrometers ) Si(x) N(y) support beams that reduce the thermal conductance G between the substrate and the optical absorber. To reduce the heat capacity of the absorber and make the response time tau fast enough for BLISS, our absorbers are patterned into a mesh geometry with a fill factor of less than 10%. We use a bilayer of Ti/Au to make the effective impedance of the absorber match the impedance of the incoming radiation for each band. Measurements of the response time of the metallized absorbers to heat pulses show that their heat capacity exceeds the predictions of the Debye model. Our results are suggestive that the surface of the low pressure chemical vapor deposition (LPCVD) Si(x)N(y) used in the absorbers' construction is the source of microstates that dominate the heat capacity.

far-IR spectrometer↗
NASA NTRS2015

Giant-Planet Chemistry: Ammonium Hydrosulfide (NH4SH), Its IR Spectra and Thermal and Radiolytic Stabilities

Here we present our recent studies of proton-irradiated and unirradiated ammonium hydrosulfide, NH4SH, a compound predicted to be an important tropospheric cloud component of Jupiter and other giant planets. We irradiated both crystalline and amorphous NH4SH at 10-160 K and used IR spectroscopy to observe and identify reaction products in the ice, specifically NH3 and long-chained sulfur-containing ions. Crystalline NH4SH was amorphized during irradiation at all temperatures studied with the rate being the fastest at the lowest temperatures. Irradiation of amorphous NH4SH at approximately 10-75 K showed that 60-80% of the NH4 + remained when equilibrium was reached, and that NH4SH destruction rates were relatively constant within this temperature range. Irradiations at higher temperatures produced different dose dependence and were accompanied by pressure outbursts that, in some cases, fractured the ice. The thermal stability of irradiated NH4SH was found to be greater than that of unirradiated NH4SH, suggesting that an irradiated giant-planet cloud precipitate can exist at temperatures and altitudes not previously considered.

Jupiter↗
NASA NTRS2017

IR Spectra and Properties of Solid Acetone, an Interstellar and Cometary Molecule

Mid-infrared spectra of amorphous and crystalline acetone are presented along with measurements of the refractive index and density for both forms of the compound. Infrared band strengths are reported for the first time for amorphous and crystalline acetone, along with IR optical constants. Vapor pressures and a sublimation enthalpy for crystalline acetone also are reported. Positions of 13C-labeled acetone are measured. Band strengths are compared to gas-phase values and to the results of a density-functional calculation. A 73% error in previous work is identified and corrected.

IR spectroscopy, band strengths, astrochemistry, a↗
DOE OSTI2024

Laterally Modulating Carrier Concentration by Ion Irradiation in CdO Thin Films for Mid‐IR Plasmonics

This report demonstrates tunable carrier densities in CdO thin films through local ion irradiation, providing lateral control of mid‐IR optical properties. Ion‐solid interactions produce donor‐like defects that boost electron concentrations from the practical minimum of 2.5 × 10 19 cm −3 to a maximum of 2.5 × 10 20 cm −3 by metered ion exposure. This range is achieved using He, N, Ar, or Au ions at 1–2.8 MeV; when normalized by displacements per atom, all ion species produce comparable results. Since CdO is well‐described by the Drude model, irradiation‐tuned carrier densities directly alter the infrared dielectric function, and in turn, mid‐infrared optical properties. Further, it is demonstrated that by combining irradiation with traditional lithography, CdO films expose to ions in the presence of 3‐µm thick, patterned photoresist exhibit lateral carrier density profiles with ≈400‐nm resolution. Scanning near‐field optical microscopy reveals sharp optical interfaces with almost no companion contrast in surface morphology, microstructure, or crystallinity. Finally, CdO lateral homostructures supporting surface plasmon polaritons (SPPs) are demonstrated whose dispersion relation can be tuned through periodic patterning in a monolithic platform by simple nanofabrication. Numerical simulations show these polaritons result from strong coupling between excitations at CdO plasma frequencies and SPPs supported by the platinum substrate.

cadmium oxide↗