Microwave ionization of three-dimensional hydrogen atoms in a realistic numerical experiment

1995 ◽  
Vol 12 (4) ◽  
pp. 505 ◽  
Author(s):  
Andreas Buchleitner ◽  
Dominique Delande ◽  
Jean-Claude Gay
Keyword(s):  
Numerical Experiment ◽  
Three Dimensional ◽  
Hydrogen Atoms ◽  
Microwave Ionization

Ab Initio Determination of a New Complex Structure (55 Non-Hydrogen Atoms) from Synchrotron Powder Data: An Uncommon Nickel Succinate, Ni7(C4H4O4)4(OH)6(H2O)3•7H2O

2004 ◽  
Vol 443-444 ◽  
pp. 333-336
Author(s):  
N. Guillou ◽  
C. Livage ◽  
W. van Beek ◽  
G. Férey
Keyword(s):  
Ab Initio ◽  
Complex Structure ◽  
Three Dimensional ◽  
Free Water ◽  
Hydrogen Atoms ◽  
Monoclinic System ◽  
Synchrotron Powder Diffraction ◽  
Chloride Hexahydrate ◽  
Autogenous Pressure

Ni7(C4H4O4)4(OH)6(H2O)3. 7H2O, a new layered nickel(II) succinate, was prepared hydrothermally (180°C, 48 h, autogenous pressure) from a 1:1.5:4.1:120 mixture of nickel (II) chloride hexahydrate, succinic acid, potassium hydroxide and water. It crystallizes in the monoclinic system (space group P21/c, Z = 4) with the following parameters a = 7.8597(1) Å, b = 18.8154(3)Å, c = 23.4377(4) Å,ϐ = 92.0288(9)°, and V = 3463.9(2) Å3. Its structure, which contains 55 non-hydrogen atoms, was solved ab initio from synchrotron powder diffraction data. It can be described from hybrid organic-inorganic layers, constructed from nickel oxide corrugated chains. These chains are built up from NiO6hexameric units connected via a seventh octahedron. Half of the succinates decorate the chains, and the others connect them to form the layers. The three dimensional arrangement is ensured by hydrogen bonds directly between two adjacent layers and via free water molecules.

scholarly journals Developing the Flow Path For the K-1250-6.9/25 Turbine Unit Using the Optimal Design Methods

2021 ◽  
pp. 15-18
Author(s):  
Ihor Palkov ◽  
Sergii Palkov ◽  
Oleh Ishchenko ◽  
Olena Avdieieva
Keyword(s):  
Numerical Experiment ◽  
Cross Sections ◽  
Turbine Unit ◽  
Current Flow ◽  
Three Dimensional ◽  
Flow Path ◽  
Three Dimensional Model ◽  
Flow Paths ◽  
Intermediate Pressure ◽  
Blade System

The paper considers the main principles that are used to develop the flow paths (FP) of the high-pressure cylinders (HPC), intermediate-pressure cylinders (IPC), and low-pressure cylinders (LPC) for the K-1250-6.9/25 turbine unit. It describes approaches to the numerical experiment when designing flow paths, the advantage of which is lower labor, time and financial costs and higher informativeness compared to the physical experiment on flow paths. When designing the flow paths of high- and intermediate-pressure cylinders (HIPC), the numerical experiment is performed using the three-dimensional viscous-flow method. For this purpose, a three-dimensional model of the blade system in the flow path is built, which consists of a large number of finite volumes (elements) in the shape of hexagons, in each of which the integration of the equations of gas dynamics is performed. When developing LPC, the method of parameterization and analytical profiling of the blade crown sections is used, where the profiles are described by the curves of the fourth and fifth orders with the condition of providing the minimum value of the maximum curvature and monotonicity of variation of the three-dimensional blade geometry along height. This method allows obtaining the optimal profiles of the cross sections of the blades, which correspond to the current flow lines to the fullest extent, and minimizing the profile energy losses when the flow flows around the blades.

scholarly journals 5-Methyl-1,3-phenylene bis[5-(dimethylamino)naphthalene-1-sulfonate]: crystal structure and DFT calculations

2019 ◽  
Vol 75 (7) ◽  
pp. 1079-1083
Author(s):  
Tanwawan Duangthongyou ◽  
Ramida Rattanakam ◽  
Kittipong Chainok ◽  
Songwut Suramitr ◽  
Thawatchai Tuntulani ◽  
...  
Keyword(s):  
Dft Calculations ◽  
Energy Gap ◽  
Rotation Axis ◽  
Three Dimensional ◽  
Hydrogen Atoms ◽  
Lumo Energy ◽  
Compound C ◽  
Dansyl Group ◽  
Weak Hydrogen Bonds ◽  
Homo Lumo

The title compound, C31H30N2S2O6, possesses crystallographically imposed twofold symmetry with the two C atoms of the central benzene ring and the C atom of its methyl substituent lying on the twofold rotation axis. The two dansyl groups are twisted away from the plane of methylphenyl bridging unit in opposite directions. The three-dimensional arrangement in the crystal is mainly stabilized by weak hydrogen bonds between the sulfonyl oxygen atoms and the hydrogen atoms from the N-methyl groups. Stacking of the dansyl group is not observed. From the DFT calculations, the HOMO–LUMO energy gap was found to be 2.99 eV and indicates n→π* and π→π* transitions within the molecule.

Structure and conformation of the hydrochloride of pseudoisocytidine, an antileukemic C-nucleoside

1980 ◽  
Vol 58 (16) ◽  
pp. 1633-1638 ◽  
Author(s):  
George I. Birnabaum ◽  
Kyoichi A. Watanabe ◽  
Jack J. Fox
Keyword(s):  
Heavy Atom ◽  
Three Dimensional ◽  
Direct Methods ◽  
Dimensional Structure ◽  
Side Chain ◽  
Hydrogen Atoms ◽  
Triclinic Space Group ◽  
X Ray Crystallography ◽  
Cell Dimensions ◽  
Sugar Ring

The three-dimensional structure of pseudoisocytidine hydrochloride was determined by X-ray crystallography. The crystals belong to the triclinic space group P1 and the cell dimensions are a = 6.623(2), b = 8.053(2), c = 6.201(2) Å, α = 108.35(2), β = 101.36(2), γ = 93.54(2) °. Intensity data were measured with a diffractometer and the structure was solved by a combination of heavy-atom and direct methods. Least-squares refinement, which included hydrogen atoms, converged at R = 0.040. The conformation about the glycosyl bond is anti (χCC = 21.6°), the pucker of the furanose ring is C(1′)exo, and the conformation of the —CH2OH side chain is gauche–trans (t). An examination of bond lengths indicates that of the three main resonance forms of the isocytosine cation the fully conjugated one contributes more to the structure than the cross-conjugated one. Bond angles in the sugar ring reflect its rare conformation.

scholarly journals Hydrology of Drained Peatland Forest: Numerical Experiment on the Role of Tree Stand Heterogeneity and Management

Forests ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 645 ◽  
Author(s):  
Leena Stenberg ◽  
Kersti Haahti ◽  
Hannu Hökkä ◽  
Samuli Launiainen ◽  
Mika Nieminen ◽  
...  
Keyword(s):  
Water Balance ◽  
Numerical Experiment ◽  
Stand Structure ◽  
Three Dimensional ◽  
Stem Volume ◽  
Tree Stand ◽  
Management Scenarios ◽  
Site Water ◽  
Stand Thinning

A prerequisite for sustainable peatland forestry is sufficiently low water table (WT) level for profitable tree production. This requires better understanding on controls and feedbacks between tree stand and its evapotranspiration, drainage network condition, climate, and WT levels. This study explores the role of spatial tree stand distribution in the spatiotemporal distribution of WT levels and site water balance. A numerical experiment was conducted by a three-dimensional (3-D) hydrological model (FLUSH) applied to a 0.5 ha peatland forest assuming (1) spatially uniform interception and transpiration, (2) interception and transpiration scaled with spatial distributions of tree crown and root biomass, and (3) the combination of spatially scaled interception and uniform transpiration. Site water balance and WT levels were simulated for two meteorologically contrasting years. Spatial variations in transpiration were found to control WT levels even in a forest with relatively low stand stem volume (<100 m3/ha). Forest management scenarios demonstrated how stand thinning and reduced drainage efficiency raised WT levels and increased the area and duration of excessively wet conditions having potentially negative economic (reduced tree growth) and environmental (e.g., methane emissions, phosphorus mobilization) consequences. In practice, silvicultural treatment manipulating spatial stand structure should be optimized to avoid emergence of wet spots.

Hydrogen atoms in the presence of a homogeneous magnetic field: a variational approach

1978 ◽  
Vol 56 (12) ◽  
pp. 1545-1548 ◽  
Author(s):  
H. S. Brandi ◽  
Belita Koiller
Keyword(s):  
Magnetic Field ◽  
Hydrogen Atom ◽  
Excited States ◽  
Three Dimensional ◽  
Homogeneous Magnetic Field ◽  
Basis Functions ◽  
Variational Parameter ◽  
Hydrogen Atoms ◽  
Wide Range ◽  
Free Hydrogen

We propose a variational scheme to obtain the spectrum of the hydrogen atom in the presence of an external homogeneous magnetic field. We use two different sets of basis functions to diagonalize the Hamiltonian describing the system, namely, the eigenfunctions of the free hydrogen atom and of the three-dimensional harmonic oscillator, both having their radial coordinates properly scaled by a variational parameter. Because of its characteristics, the present approach is suited to describe the ground state as well as an infinite number of excited states for a wide range of magnetic field strengths.

scholarly journals A cinnamaldehyde Schiff base ofS-(4-methylbenzyl) dithiocarbazate: crystal structure, Hirshfeld surface analysis and computational study

2017 ◽  
Vol 73 (4) ◽  
pp. 543-549 ◽  
Author(s):  
Enis Nadia Md Yusof ◽  
Mohamed I. M. Tahir ◽  
Thahira B. S. A. Ravoof ◽  
Sang Loon Tan ◽  
Edward R. T. Tiekink
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Surface Analysis ◽  
Mirror Symmetry ◽  
Computational Study ◽  
Three Dimensional ◽  
Hirshfeld Surface ◽  
Hirshfeld Surface Analysis ◽  
Hydrogen Atoms ◽  
Benzyl Substituent

The title dithiocarbazate ester (I), C18H18N2S2[systematic name: (E)-4-methylbenzyl 2-[(E)-3-phenylallylidene]hydrazinecarbodithioate, comprises an almost planar central CN2S2residue [r.m.s. deviation = 0.0131 Å]. The methylene(tolyl-4) group forms a dihedral angle of 72.25 (4)° with the best plane through the remaining non-hydrogen atoms [r.m.s. deviation = 0.0586 Å] so the molecule approximates mirror symmetry with the 4-tolyl group bisected by the plane. The configuration about both double bonds in the N—N=C—C=C chain isE; the chain has an alltransconformation. In the crystal, eight-membered centrosymmetric thioamide synthons, {...HNCS}2, are formedviaN—H...S(thione) hydrogen bonds. Connections between the dimersviaC—H...π interactions lead to a three-dimensional architecture. A Hirshfeld surface analysis shows that (I) possesses an interaction profile similar to that of a closely related analogue with anS-bound benzyl substituent, (II). Computational chemistry indicates the dimeric species of (II) connectedviaN—H...S hydrogen bonds is about 0.94 kcal mol−1more stable than that in (I).

Sign in / Sign up

Export Citation Format

Share Document