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Theoretical microwave spectral constants have been computed for C2N, C3H, and C2N(+). For C2N these are compared with values obtained from optical data. Calculated hyperfine constants are also presented for HNC, DNC, and HCNH(+). The possibility of observing these species in dense interstellar clouds is discussed.
MnB4H24(C2N)2 crystallizes in the tetragonal I-42d space group. The structure is zero-dimensional and consists of eight MnB4H24(C2N)2 clusters. Mn2+ is bonded in a 8-coordinate geometry to eight H+0.83+ atoms. There are a spread of Mn–H bond distances ranging from 2.00–2.10 Å. There are two inequivalent B sites. In the first B site, B is bonded to one N3- and three H+0.83+ atoms to form BH3N tetrahedra that share a cornercorner with one BH3N tetrahedra and corners with two equivalent CH3N tetrahedra. The B–N bond length is 1.58 Å. There are a spread of B–H bond distances ranging from 1.21–1.25 Å. In the second B site, B is bonded to one N3- and three H+0.83+ atoms to form BH3N tetrahedra that share a cornercorner with one BH3N tetrahedra and corners with two equivalent CH3N tetrahedra. The B–N bond length is 1.58 Å. There are a spread of B–H bond distances ranging from 1.21–1.26 Å. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to one N3- and three H+0.83+ atoms to form CH3N tetrahedra that share a cornercorner with one CH3N tetrahedra and corners with two equivalent BH3N tetrahedra. The C–N bond length is 1.49 Å. There is one shorter (1.09 Å) and two longer (1.10 Å) C–H bond length. In the second C4- site, C4- is bonded to one N3- and three H+0.83+ atoms to form CH3N tetrahedra that share a cornercorner with one CH3N tetrahedra and corners with two equivalent BH3N tetrahedra. The C–N bond length is 1.49 Å. All C–H bond lengths are 1.10 Å. There are two inequivalent N3- sites. In the first N3- site, N3- is bonded in a tetrahedral geometry to two equivalent B and two equivalent C4- atoms. In the second N3- site, N3- is bonded in a tetrahedral geometry to two equivalent B and two equivalent C4- atoms. There are twelve inequivalent H+0.83+ sites. In the first H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom. In the second H+0.83+ site, H+0.83+ is bonded in an L-shaped geometry to one Mn2+ and one B atom. In the third H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom. In the fourth H+0.83+ site, H+0.83+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B atom. In the fifth H+0.83+ site, H+0.83+ is bonded in a distorted L-shaped geometry to one Mn2+ and one B atom. In the sixth H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom. In the seventh H+0.83+ site, H+0.83+ is bonded in an L-shaped geometry to one Mn2+ and one B atom. In the eighth H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one B atom. In the ninth H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom. In the tenth H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one B atom. In the eleventh H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom. In the twelfth H+0.83+ site, H+0.83+ is bonded in a single-bond geometry to one C4- atom.
Reactivities of the structural isomers CCN(+) and CNC(+) were examined in a selected-ion flow tube at 300 + or - 5 K. The less reactive CNC(+) isomer was identified as the product of the reactions of C(+) + HCN and C(+) + C2N2; in these reactions only CNC(+) can be produced because of energy constraints. Rate coefficients and branching ratios are reported for the reactions of each isomer with H2, CH4, NH3, H2O, C2H2, HCN, N2, O2, N2O, and CO2. Ab initio calculations are presented for CCN(+) and CNC(+); a saddle point for the reaction CCN(+) yielding CNC(+) is calculated to be 195 kJ/mol above CNC(+). The results provide evidence that the more reactive CCN(+) isomer is unlikely to be present in measurable densities in interstellar clouds.
A coal-to-nuclear (C2N) transition means siting a nuclear reactor at the site of a recently retired coal power plant. Three overarching questions from the C2N transition guide this research: where in the United States are retired coal facilities located and what factors make a site feasible for transition; what factors of technology, cost, and project timeline drive investor economics over such a decision; and how will C2N impact local communities? The study team evaluated the siting characteristics of recently retired plants and those operating coal-fired power plant sites run by a utility or an independent power producer utilizing publicly available data to screen U.S. coal power plant sites to nuclear-feasible locations. After screening all retired coal sites to a set of 157 potential candidates and screening operating sites to a set of 237 candidates, the study team estimates that 80% of retired and operating coal power plant sites that were evaluated have the basic characteristics needed to be considered amenable to host an advanced nuclear reactor. For the recently retired plant sites evaluated, this represents a capacity potential of 64.8 GWe to be backfit at 125 sites. For the operating plant sites evaluated, this represents a capacity potential of 198.5 GWe to be backfit at 190 sites. This report evaluates a case study for the detailed impacts and potential outcomes from a C2N transition. Based on the nuclear technology choices and sizes evaluated to replace a large coal plant of 1,200 MWe generation capacity at the case study site, nuclear overnight costs of capital could decrease by 15% to 35% when compared to a greenfield construction project, through the reuse of infrastructure from the coal facility. Nuclear replacement designs can have a lower capacity size because nuclear power plants run at higher capacity factors than coal power plants. In the case study replacing coal capacity with 924 GWe of nuclear capacity, the study team found regional economic activity could increase by as much as $\$275 million$ and add 650 new, permanent jobs to the region of analysis. The evaluated site choice in the report is hypothetical for analysis purposes only and based on available data and documented assumptions. Consequently, the findings only inform at a general level. A community, investor, or other interested stakeholder can use these results to set up a detailed, in-depth analysis for a specific application of interest, such as evaluating a C2N transition of a specific coal power plant and a specific nuclear technology design. The report was subjected to independent peer reviews by experts in systems engineering and regional economic modeling to evaluate analysis and assumptions.
In a recent paper, Sittler et al., (2010) presented new results on the T9 encounter by the Cassini spacecraft when it passed through Titan s induced magnetotail. Two crossings were observed, but the first crossing, event 1, is thought to be out flowing ionosphere plasma. T9 is ideal for CAPS IMS probing of the ionosphere, since the ion densities at the higher altitudes of the T9 flyby approx. 10,000 km, allows measurements to be made down to 1 eV without saturating its detectors. Sittler et al., (2010) reported possible detection of NH4+ ions, but favored the detection of CH5+ and C2H5+ ions. In this report we investigate both the medium mass resolution (straight through (ST)) and high mass resolution (linear electric field (LEF)) composition data from the Cassini Plasma Spectrometer (CAPS) Ion Mass Spectrometer (IMS). We present a more in depth analysis of the composition data and make comparisons with ionospheric models including nitrogen chemistry such as that by Vuitton et al. (2007). The LEF data does not support NH4+ identification, but favors a CH5+ and C2H5+ identification, but also molecular ions C2N+ and CH2NH2+ are chemically allowed possibilities.
Nanocrystals (NCs) appear as a promising platform for cost effective infrared optoelectronics, while offering a simplified coupling to the CMOS platform. However, this perspective is slowed down by toxicity concerns, the most effective materials being based on Pb and Hg. There is currently a large effort to bring forth new platforms that are active in the infrared with a reduced heavy metal content. Here, in this study, the focus is on silver chalcogenides, which, thanks to a combination of inter‐ and intraband transitions, is suited to cover both short and mid wave infrared ranges. However, this material being less mature, the achieved photoluminescence (PL) appears quite broad, which is problematic for device integration. Here, it is demonstrated that a strong control over the PL spectrum can be obtained through integration into a dielectric cavity that magnifies the electric field by a factor 20 and narrows the PL full width at half maximum down to 15 nm for an emission at telecom wavelength. The PL is also highly directional to avoid most waveguiding effects which is of utmost interest for enhancing the efficiency of NC‐based light emitting diodes.
Double-atom catalysts (DACs) have emerged as an enhanced platform of single-atom catalyst for promoting electrocatalytic CO 2 reduction reaction (CO 2 RR). Herein, we present a density-functional theory study on CO 2 RR performance of seven C 2 N-supported homo- and heteronuclear DACs, denoted as M 2 @C 2 N. Our results demonstrate that there exists substantial synergistic effect of dual-metal-atom N 2 M 2 N 2 active site and C 2 N matrix on O═ C ═O bond activation. The dual-atom M 2 sites are able to drive CO 2 RR beyond C 1 products with low limiting potential (U L ). Specifically, C 2 H 4 formation is preferred on FeM@C 2 N (M = Fe, Co, Ni, Cu) versus CH 4 formation on CuM@C 2 N (M = Co, Ni, Cu). Furthermore, *CO+*CO co-binding strength can serve as a descriptor for CO 2 RR activity for making C 2 products such that the moderate binding results in the lowest U L . Remarkably, C-affinity matters most to C—C bond coupling and C 2 H 4 formation while both C- and O-affinity control CH 4 formation. Furthermore, our results provide theoretical insight into rational design of DACs for efficient CO 2 RR.