scholarly journals K‐shell shape resonances and intramolecular bond lengths. Comments on ‘‘The relationship between shape resonances and bond lengths’’

1987 ◽  
Vol 87 (5) ◽  
pp. 3253-3255 ◽  
Author(s):  
A. P. Hitchcock ◽  
J. Stöhr
Keyword(s):  
Shell Shape ◽  
Bond Lengths ◽  
The Relationship ◽  
Shape Resonances

scholarly journals The relationship between shape resonances and bond lengths

1987 ◽  
Vol 86 (5) ◽  
pp. 2765-2771 ◽  
Author(s):  
M. N. Piancastelli ◽  
D. W. Lindle ◽  
T. A. Ferrett ◽  
D. A. Shirley
Keyword(s):  
Bond Lengths ◽  
The Relationship ◽  
Shape Resonances

scholarly journals Reply to the ‘‘Comment on ‘The relationship between shape resonances and bond lengths’ ’’

1987 ◽  
Vol 87 (5) ◽  
pp. 3255-3256 ◽  
Author(s):  
M. N. Piancastelli ◽  
D. W. Lindle ◽  
T. A. Ferrett ◽  
D. A. Shirley
Keyword(s):  
Bond Lengths ◽  
The Relationship ◽  
Shape Resonances

N-(6-Amino-3,4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl) derivatives of glycine, valine, serine, threonine and methionine: interplay of molecular, molecular–electronic and supramolecular structures

2000 ◽  
Vol 56 (5) ◽  
pp. 882-892 ◽  
Author(s):  
J. N. Low ◽  
M. D. López ◽  
P. Arranz Mascarós ◽  
J. Cobo Domingo ◽  
M. L. Godino ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Three Dimensional ◽  
Computational Modelling ◽  
Carboxyl Groups ◽  
Molecular Electronic ◽  
Database Analysis ◽  
Intermolecular Hydrogen Bonds ◽  
Bond Lengths ◽  
The Relationship ◽  
Derivatives Of

In each of N-(6-amino-3,4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl)valine, C10H15N5O4 (3) (orthorhombic, P212121), N-(6-amino-3,4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl)serine monohydrate, C8H11N5O5·H2O (4) (orthorhombic, P212121), and N-(6-amino-3,4-dihydro-3-methyl-5-nitroso-4-oxopyrimidin-2-yl)threonine, C9H13N5O5(5) (monoclinic, P21), the C-nitroso fragments exhibit almost equal C—N and N—O bond lengths: the C—N range is 1.315 (3)–1.329 (3) Å and the N—O range is 1.293 (3)–1.326 (3) Å. In each compound there are also very short intermolecular O—H...O hydrogen bonds, in which carboxyl groups act as hydrogen-bond donors to the nitrosyl O atoms: the O...O distances range from 2.440 (2) to 2.504 (4) Å and the O—H...O angles lie between 161 and 163°. An interpretation of the relationship between the unusual intramolecular bond lengths and the very short intermolecular hydrogen bonds has been developed based on database analysis and computational modelling. In each of (3)–(5) there is an extensive network of intermolecular hydrogen bonds, generating three-dimensional frameworks in (3) and (5), and two-dimensional sheets in (4).

STUDY OF INVARIANT Tc IN HIGHER DOPING LEVEL Y1-xCaxBa2-xLaxCu3Oy

2005 ◽  
Vol 19 (01n03) ◽  
pp. 307-309 ◽  
Author(s):  
X. F. SUN ◽  
H. L. DU ◽  
X. F. RUI ◽  
L. ZHANG ◽  
F. WANG ◽  
...  
Keyword(s):  
Structural Change ◽  
Carrier Concentration ◽  
Doping Level ◽  
Narrow Range ◽  
Bond Lengths ◽  
The Relationship

The higher doping level Y 1-x Ca x Ba 2-x La x Cu 3 O y samples were synthesized with x from 0.25 to 0.55. Structure and superconductivity have been investigated. Comparing with the results of lower doping level, the Tc of these samples keeps almost constant when dopant increasing. While some structural characters, such as Cu (1)- O (4), Cu (2)- O (4) bond lengths change randomly in a narrow range. The relationship between Ba / La position and Tc is rather interesting. The results give another evidence that the influence of structural change on superconductivity is independent of carrier concentration.

Charge Transfer and Bond Lengths in YBa2Cu3−xMxO6+y

1989 ◽  
Vol 156 ◽  
Author(s):  
P. F. Miceli ◽  
J. M. Tarascon ◽  
L. H. Greene ◽  
P. Barboux ◽  
J. D. Jorgensen ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Neutron Scattering ◽  
Bond Valence ◽  
Bond Lengths ◽  
The Relationship

ABSTRACTWe discuss the effects of doping on the Cu chain sites in YBa2Cu3−xMxO6+y. The relationship between bond lengths obtained from neutron scattering and charge transfer is evaluated in terms of bond valence. In particular, it is concluded that removing an oxygen from the chains transfers one electron to the planes.

The shape of the Upper Carboniferous non-marine bivalve Anthraconaia in relation to the organic carbon content of the host sediment

1987 ◽  
Vol 78 (3) ◽  
pp. 177-195 ◽  
Author(s):  
R. M. C. Eagar
Keyword(s):  
Organic Carbon ◽  
Regional Distribution ◽  
Maximum Growth ◽  
Shell Shape ◽  
Marine Bivalve ◽  
Organic Carbon Content ◽  
Maximum Width ◽  
Upper Carboniferous ◽  
The Relationship ◽  
Host Sediment

ABSTRACTAnthraconaia lived on clay grade sediments. In highly variable life assemblages of the A.prolifera group of the E German Wettin Shales (Stephanian C) organic carbon percentage of the host sediment correlates with wu/m and A/L ratios of the shell (where wu is the maximum width ventral to the line of maximum growth, m, L the maximum length measured parallel to the line of the hinge, and A the length anterior to the umbo). Decrease in the organic carbon of the sediment is associated with decrease in umbonal development, elongation of the shell along the m axis, and straightening and reflection of the ventral margin; the latter becomes subparallel to the dorsum or to the m axis with a concomitant decrease in size. These results confirm and amplify earlier work on Anthraconaia in the Appalachian coalfields. The same morphological trends in relation to organic carbon characterise the Anthraconaia modiolaris group of Britain, both within a single succession in upper Westphalian A sediments in Yorkshire, and also in three shell bands of Lower Westphalian B age in S Wales, Yorkshire and central Scotland. In the last named, above the Musselband Coal, statistical formulae (of Leitch 1940) for the species A.salteri are shown to define neither the type assemblage nor its stratigraphical position. The shell-shape/organic carbon relationship has been broadly confirmed on other horizons of lower Westphalian B age in the Scottish and Pennine coalfields. Far from embarrassing the stratigrapher, the relationship, which reflects ultimately trophic level of deltaic palaeoenvironments, contributes to our understanding of non-marine bivalve faunas, especially of the apparent regional distribution of ‘species’ of Anthraconaia.

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