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At least 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1980

Neutral cometary atmospheres. III - Acceleration of cometary CN by solar radiation pressure

The acceleration of cometary CN radicals due to solar radiation pressure has been determined by fitting Monte Carlo models to nine observed sunward-tailward pairs of brightness profiles of the (0-0) band of CN at 3883 A. The profiles were determined from spectrograms of comets Bennett 1970 II and West 1976 VI. The values of the observed acceleration agree with those computed from resonance fluorescence calculations to within the expected uncertainties. This provides an independent confirmation of the identification of the observed scale lengths with the photochemical lifetimes and velocities associated with the production of observed cometary CN by the photodissociation of HCN. The ratio of the intensity of the (0-1) band of CN at 4216 A to the (0-0) band at 3883 A has been determined from spectrograms of comet West, and is compared with theoretical values.

Combi, M. R.↗
NASA NTRS1988

An investigation into periodicities in the morphology of CN jets in comet P/Halley

The paper presents an analysis of a set of CCD images of Comet Halley which were taken in the light of the CN radical to search for evidence of a 2.25-day and/or a 7.37-day periodicity in the evolution of the CN jets. It is found that, for a phase sorted set of CCD images, the geometry of the CN jets is more easily understood when a 7.37-day periodicity is assumed. The extent of the CN jets indicates a dominant periodicity that is greater than 2.25 days.

Hoban, S.↗
NASA NTRS1987

Theoretical study of the dissociation energy and the red and violet band systems of CN

The dissociation energy (D sub O) of CN is determined to be 7.65 + or - 0.06 eV. This corresponds to delta H sub f (CN) = 105.3 + or - 1.5 kcal/mole, in excellent agreement with Engleman and Rouse (1975), but considerably larger than the recent value deduced from shock-tube studies by Colket (1984). The result is obtained not only from extensive ab initio MRCI calculations using a very large Gaussian basis set, but also from extrapolation of the directly computed value by comparison of computed and experimental results fo NO, C2, and N2. As an additional calibration of the methods, the D sub O value for CN was computed from the corresponding value for CN(-) using the experimental electron affinity data. The lifetime of the nu prime = 0 level of the violet (B 2 sigma + yields X 2 sigma +) system was computed to be 62.4 ns, in good agreement with both experiment and previous calculations. Lifetimes for the red (A 2 pi yields X 2 sigma +) system decrease with increasing nu prime, which is consistent both with the recent experiment and calculations. While the computed lifetimes are significantly longer that those obtained from the experiment, they are shorter than those deduced from an analysis of the solar spectrum. However the D sub O and f (sub OO) are consistent with Lambert's model for the solar spectrum.

Bauschlicher, Charles W., Jr.↗
NASA NTRS1990

Spectrum synthesis of CN in comets

The CN B-X (0-0) R branch fluorescence spectra for three comets (Austin, Bennett, Halley) were calculated and compared to the observed spectra. The synthesized spectrum in each case was shifted to allow for the comparison of the individual line intensities. The Swings effect (excitation of CN band in comet spectra by solar fluorescence) is clearly visible. In addition to the R(0-0) band in the CN spectrum, the P(1-1) band also contributes lines in the spectral region of observation. This branch was calculated and compared to P/Halley. The overall agreement between observations and the CN spectral model is quite good. An exception to this statement would be the high J rotation lines intensities within the R(0-0) branch of P/Halley. Additional analysis is necessary to determine if this difference is due to mechanisms in addition to fluorescence (e.g., collisions).

Kleine, Marvin↗
NASA NTRS1991

CN and HCN in the infrared spectrum of IRC + 10216

The abundance of HCN in the inner circumstellar shell of IRC + 10216 has been remeasured using the 12-micron nu2 band. The 12-micron lines are less saturated than HCN 3-micron lines previously detected in the spectrum of IRC + 10216. The observed 12-micron HCN line is formed in the circumstellar shell from about 4 to 12 R sub * in accord with a photospheric origin for HCN. The derived HCN abundance in the 4 to 12 R sub* region is 4 x 10 exp-5 and the column density is 7 x 10 exp 18/sq cm. The 5-micron CN vibration-rotation fundamental band was detected for the first time in an astronomical source. Using four CN lines, the CN column density was determined to be 2.6 x 10 exp 15/sq cm and the rotational temperature to be 8 +/-2 K. The peal radial abundance is 1 x 10 exp -5. The values for the temperature and abundance are in good agreement with microwave results and with the formation of CN from the photolysis of HCN.

Wiedemann, G. R.↗
NASA NTRS1992

P/Halley: Spatial distribution and scale lengths for C2, CN, NH2, and H2O

From P/Halley, long slit spectroscopic exposures on 12 dates, extending from Oct. 1985 to May 1986, spatial profiles were obtained for emissions by C2, CN, NH2, and OI ((sup 1)D). Examples of our derived spatial profiles are given. The qualitative trend of the scale lengths for the different species is nicely exemplified in this example. C2 has the longest parent scale length followed by CN and NH2. OI which tracks the parent H2O distribution is quite narrow but slightly wider than the continuum profile which has a center essentially indistinguishable from the stellar seeing disk. Comparison of C2 and CN also shows that C2 is falling off faster in the wings so that the daughter scale length of CN must be larger than that of C2.

Fink, Uwe↗
DOE OSTI2024

Crystal structure and synchrotron X-ray powder reference pattern for the porous pillared cyanonickelate, Ni(3-amino-4,4′-bipyridine)[Ni(CN) 4 ]

The structure of Ni(3-amino-4,4′-bipyridine)[Ni(CN) 4 ] (or known as Ni-BpyNH 2 ) in powder form was determined using synchrotron X-ray diffraction and refined using the Rietveld refinement technique (R = 8.8%). The orthorhombic (Cmca) cell parameters were determined to be a = 14.7218(3) Å, b = 22.6615(3) Å, c = 12.3833(3) Å, V = 4131.29(9) Å 3 , and Z = 8. Ni-BpyNH 2 forms a 3-D network, with a 2-D Ni(CN) 4 net connecting to each other via the BpyNH 2 ligands. Further, there are two independent Ni sites on the net. The 2-D nets are connected to each other via the bonding of the pyridine “N” atom to Ni2. The Ni2 site is of six-fold coordination to N with relatively long Ni2–N distances (average of 2.118 Å) as compared to the four-fold coordinated Ni1–C distances (average of 1.850 Å). The Ni(CN) 4 net is arranged in a wave-like fashion. The functional group, –NH 2 , is disordered and was found to be in the m-position relative to the N atom of the pyridine ring. Instead of having a unique position, N has ¼ site occupancy in each of the four m-positions. The powder reference diffraction pattern for Ni-BpyNH 2 was prepared and submitted to the Powder Diffraction File (PDF) at the International Centre of Diffraction Data (ICDD).

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AgB(CN)4 by Materials Project

BAg(CN)4 is Tetraauricupride structured and crystallizes in the cubic P-43m space group. The structure is zero-dimensional and consists of one boron, metallic molecule and one Ag(CN)4 cluster. In the Ag(CN)4 cluster, Ag1+ is bonded in a tetrahedral geometry to four equivalent N3- atoms. All Ag–N bond lengths are 2.26 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.16 Å. N3- is bonded in a linear geometry to one Ag1+ and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsB(CN)4 by Materials Project

Cs(CN)4B crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional and consists of four boron molecules and one Cs(CN)4 framework. In the Cs(CN)4 framework, Cs1+ is bonded in a 8-coordinate geometry to eight equivalent N3- atoms. There are four shorter (3.30 Å) and four longer (3.44 Å) Cs–N bond lengths. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a distorted single-bond geometry to two equivalent Cs1+ and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CuB(CN)4 by Materials Project

BCu(CN)4 is Tetraauricupride structured and crystallizes in the cubic P-43m space group. The structure is zero-dimensional and consists of one boron molecule and one Cu(CN)4 cluster. In the Cu(CN)4 cluster, Cu1+ is bonded in a tetrahedral geometry to four equivalent N3- atoms. All Cu–N bond lengths are 1.95 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.16 Å. N3- is bonded in a linear geometry to one Cu1+ and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on RbB(CN)4 by Materials Project

Rb(CN)4B crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional and consists of four boron molecules and one Rb(CN)4 framework. In the Rb(CN)4 framework, Rb1+ is bonded in a 8-coordinate geometry to eight equivalent N3- atoms. There are four shorter (3.11 Å) and four longer (3.33 Å) Rb–N bond lengths. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a distorted single-bond geometry to two equivalent Rb1+ and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TlB(CN)4 by Materials Project

BTl(CN)4 crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional and consists of four boron molecules and one Tl(CN)4 framework. In the Tl(CN)4 framework, Tl1+ is bonded in a 8-coordinate geometry to eight equivalent N3- atoms. There are four shorter (3.03 Å) and four longer (3.32 Å) Tl–N bond lengths. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.17 Å. N3- is bonded in a distorted single-bond geometry to two equivalent Tl1+ and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2FeNi(CN)6 by Materials Project

(K)2FeNi(CN)6 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is zero-dimensional and consists of four iron molecules, eight potassium molecules, and four Ni(CN)6 clusters. In each Ni(CN)6 cluster, Ni2+ is bonded in an octahedral geometry to six equivalent N3- atoms. All Ni–N bond lengths are 2.04 Å. C+1.83+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. N3- is bonded in a linear geometry to one Ni2+ and one C+1.83+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb2LiCo(CN)6 by Materials Project

Rb2Li(CN)6Co crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of two cobalt molecules and one Rb2Li(CN)6 framework. In the Rb2Li(CN)6 framework, Rb1+ is bonded in a 8-coordinate geometry to eight N3- atoms. There are a spread of Rb–N bond distances ranging from 3.12–3.61 Å. Li1+ is bonded in an octahedral geometry to six N3- atoms. There are a spread of Li–N bond distances ranging from 2.24–2.33 Å. There are three inequivalent C+2.33+ sites. In the first C+2.33+ site, C+2.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the second C+2.33+ site, C+2.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the third C+2.33+ site, C+2.33+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted bent 150 degrees geometry to two equivalent Rb1+, one Li1+, and one C+2.33+ atom. In the second N3- site, N3- is bonded in a 2-coordinate geometry to three equivalent Rb1+, one Li1+, and one C+2.33+ atom. In the third N3- site, N3- is bonded in a distorted bent 150 degrees geometry to three equivalent Rb1+, one Li1+, and one C+2.33+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2NaCr(CN)6 by Materials Project

Cs2Na(CN)6Cr crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of two chrom molecules and one Cs2Na(CN)6 framework. In the Cs2Na(CN)6 framework, Cs1+ is bonded in a 4-coordinate geometry to four N3- atoms. There are a spread of Cs–N bond distances ranging from 3.31–3.49 Å. Na1+ is bonded in an octahedral geometry to six N3- atoms. There are a spread of Na–N bond distances ranging from 2.50–2.56 Å. There are three inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the second C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the third C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted bent 150 degrees geometry to two equivalent Cs1+, one Na1+, and one C2+ atom. In the second N3- site, N3- is bonded in a 2-coordinate geometry to one Cs1+, one Na1+, and one C2+ atom. In the third N3- site, N3- is bonded in a distorted bent 150 degrees geometry to one Cs1+, one Na1+, and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb2LiFe(CN)6 by Materials Project

Rb2Li(CN)6Fe crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of two iron molecules and one Rb2Li(CN)6 framework. In the Rb2Li(CN)6 framework, Rb1+ is bonded in a 3-coordinate geometry to six N3- atoms. There are a spread of Rb–N bond distances ranging from 3.12–3.48 Å. Li1+ is bonded in an octahedral geometry to six N3- atoms. There are a spread of Li–N bond distances ranging from 2.24–2.33 Å. There are three inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the second C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the third C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a distorted bent 150 degrees geometry to two equivalent Rb1+, one Li1+, and one C2+ atom. In the second N3- site, N3- is bonded in a 2-coordinate geometry to two equivalent Rb1+, one Li1+, and one C2+ atom. In the third N3- site, N3- is bonded in a distorted bent 150 degrees geometry to two equivalent Rb1+, one Li1+, and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb2NaCr(CN)6 by Materials Project

Rb2Na(CN)6Cr crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of two chromium molecules and one Rb2Na(CN)6 framework. In the Rb2Na(CN)6 framework, Rb1+ is bonded in a 2-coordinate geometry to five N3- atoms. There are a spread of Rb–N bond distances ranging from 3.07–3.44 Å. Na1+ is bonded in an octahedral geometry to six N3- atoms. There are four shorter (2.53 Å) and two longer (2.57 Å) Na–N bond lengths. There are three inequivalent C2+ sites. In the first C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the second C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. In the third C2+ site, C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a 2-coordinate geometry to two equivalent Rb1+, one Na1+, and one C2+ atom. In the second N3- site, N3- is bonded in a 1-coordinate geometry to two equivalent Rb1+, one Na1+, and one C2+ atom. In the third N3- site, N3- is bonded in a 2-coordinate geometry to one Rb1+, one Na1+, and one C2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb2FeCu(CN)6 by Materials Project

FeRb2Cu(CN)6 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional and consists of four iron molecules and one Rb2Cu(CN)6 framework. In the Rb2Cu(CN)6 framework, Rb1+ is bonded to twelve equivalent N3- atoms to form distorted RbN12 cuboctahedra that share corners with twelve equivalent RbN12 cuboctahedra, faces with six equivalent RbN12 cuboctahedra, and faces with four equivalent CuN6 octahedra. All Rb–N bond lengths are 3.68 Å. Cu1+ is bonded to six equivalent N3- atoms to form CuN6 octahedra that share faces with eight equivalent RbN12 cuboctahedra. All Cu–N bond lengths are 2.10 Å. C2+ is bonded in a single-bond geometry to one N3- atom. The C–N bond length is 1.18 Å. N3- is bonded in a linear geometry to four equivalent Rb1+, one Cu1+, and one C2+ atom.

36 MATERIALS SCIENCE↗